Interaction of microplastics with heavy metals in soil: Mechanisms, influencing factors and biological effects.

Microplastics (MPs) and heavy metals (HMs) in soil contamination are considered an emerging global problem that poses environmental and health risks. However, their interaction and potential biological effects remain unclear. Here, we reviewed the interaction of MPs with HMs in soil, including its mechanisms, influencing factors and biological effects. Specifically, the interactions between HMs and MPs mainly involve sorption and desorption. The type, aging, concentration, size of MPs, and the physicochemical properties of HMs and soil have significant impacts on the interaction. In particular, MP aging affects specific surface areas and functional groups. Due to the small size and resistance to decomposition characteristics of MPs, they are easily transported through the food chain and exhibit combined biological effects with HMs on soil organisms, thus accumulating in the human body. To comprehensively understand the effect of MPs and HMs in soil, we propose combining traditional experiments with emerging technologies and encouraging more coordinated efforts.

A review on invasive false indigo bush (Amorpha fruticosa L.): Nuisance plant with multiple benefits.

Increased mobility of people around the globe has facilitated transferring species to new environments, where some have found suitable conditions and even become invasive. False indigo-bush (Amorpha fruticosa L.) is a plant native to North America but has intentionally or unintentionally spread over the Northern Hemisphere, where it often becomes invasive. The plant is especially easily dispersed within the watersheds of large rivers, where seasonal flooding is regular. Seeds and other propagules are buoyant, and when the water recedes, new plants emerge, forming dense thickets where only a few other species can co-exist. In order to sustain native biodiversity, spread control is needed. However, mechanical control and eradication measures currently in use are labor demanding and costly, while application of herbicides is limited. On the other hand, the plant possesses a number of beneficial properties, such as phytochemical applications (medical and insecticidal effects), biocoenotic uses (honey plant, ornamental features), and ecosystem services (soil stabilization, provision of food for animals, and fiber and biomass for industry, e.g., nanocellulose). For the reasons above mentioned, the plant is considered quite controversial, and the paper discusses both aspects: potential detrimental effects when introduced to new habitats and its beneficial uses for human society. In addition, the paper presents alternative measures of spreading control (e.g., grazing) and argues that exploiting it for beneficial purposes might help spread control, thus covering the expenses of controlling its distribution.

Association between the pri-miR-26a-1 rs7372209 C>T polymorphism and cancer susceptibility: multivariate analysis and trial sequential analysis.

MiR-26 has been suggested to play a tumor-suppressive role in cancer development, which could be influenced by the mutate pri-miR-26ª-1. Molecular epidemiological studies have demonstrated some inconsistent associations between pri-miR-26ª-1 rs7372209 C>T polymorphism and cancer risk. We therefore performed this meta-analysis with multivariate statistic method to comprehensively evaluate the associations between rs7372209 C>T polymorphism and cancer risk. Eleven publications involving 6,709 patients and 6,514 controls were identified. Multivariate analysis indicated that the over-dominant genetic model was most likely. Pooled results indicated no significant association in the overall population (CC+TT vs. CT: OR=1.08, 95%CI=0.96-1.22, P=0.20, I2=54.4%), as well as the subgroup analysis according to ethnicity, control source, tumor locations, and HWE status of controls. In addition, heterogeneity, accumulative, sensitivity analysis, publication bias and trial sequential analysis (TSA) were conducted to test the statistical power. Overall, our results indicated that the pri-miR-26a-1 rs7372209 C>T polymorphism may not be a potential risk for cancer development.

Early-TIPS Versus Current Standard Therapy for Acute Variceal Bleeding in Cirrhosis Patients: A Systemic Review With Meta-analysis.

BACKGROUND: The survival of early placement (within 72h after admission) of transjugular intrahepatic portosystemic shunts (early-TIPS) in patients with cirrhosis and acute variceal bleeding (AVB) is controversial. OBJECTIVES: We performed a systemic review and meta-analysis to assess whether early-TIPS could improve survival in patients with cirrhosis and acute variceal bleeding. METHODS: A systematic search of the literature was conducted in PubMed, EMBASE, and Cochrane Library published before 25 June 2019 for eligible studies that compared early-TIPS with a combination of endoscopic variceal ligation (EVL) and pharmacotherapy in the therapeutic effect in AVB patients. RESULTS: A total of five studies with 1,754 participants were enrolled. The early-TIPS demonstrated a significant improvement in prevention of treatment failure (OR=0.11,95%CI=0.05-0.23), 6-weeks mortality (OR=0.24,95%CI=0.13-0.46), rebleeding within 6 weeks (OR=0.21,95%CI=0.12-0.36), rebleeding within 1 year (OR=0.16,95%CI=0.07-0.36), new or worsening ascites (OR=0.33,95%CI=0.21-0.53), except in encephalopathy (OR=1.29,95%CI=0.996-1.67). For 1-year mortality, a significant prior effect was also observed in early-TIPS (OR=0.64,95%CI=0.46-0.90), and the beneficial effect in Child-Pugh C patients (OR=0.35,95%CI=0.18-0.68) was equal to Child-Pugh B patients (OR=0.34,95%CI=0.25-0.58). No difference in liver transplantation and mortality caused by liver failure was observed. CONCLUSIONS: Early covered-TIPS could be recommended for the management of AVB patients in cirrhosis demonstrating a significant improvement in treatment failure, both short- and long-term mortality, rebleeding risk, and new or worsening ascites compared to standard therapy, especially for high-risk AVB patients. It will also apply to patients with Child-Pugh A until solutions to prevent hepatic encephalopathy in future research are found.

Conserved function of Pacific cod Caspase-3 in apoptosis.

Apoptosis plays a significant role in the cellular immune responses against infections, especially those related to viruses. Across various species, Caspase 3 is a prominent mediator of apoptosis and participates in the cell death signaling cascade. However, its role remains relatively unknown in cod fish. In this study, we aimed to reveal the role of Pacific cod Caspase-3 (GmCasp3) in apoptosis and its evolutionary position. Our results showed that the GmCasp3 cDNA contains an open reading frame of 864 nucleotides; that codes for 287 amino acids long protein with a molecular weight of 32.03 kDa. The sequence alignments and 3-D model indicated that GmCasp3 contained highly conserved domains, such as "QACRG", "GSWFI" and "HG" active sites, however, the phylogenetic tree analysis revealed that both GmCasp3 and Atlantic cod caspase-3 clustered together are far from the high vertebrate branch, indicating they are at a lower position in vertebrate evolution. Red fluorescent labeling vector pDsRed2-C1-GmCasp3 was constructed and it was transfected into EPC cell lines. The result showed that GmCasp3 protein was distribute in the protoplasm and expressed in apoptotic cell debris. Moreover, the GmCasp3 enzyme activity increased with the increased post-transfection analysis time, while the genome DNA was visibly fragmented at 36 h post transfection. Flow cytometry analysis showed that the proportion of apoptosis cells increased from 12 h to 24 h post transfection. In conclusion, the conserved functions of GmCasp3 in apoptosis indicated that Pacific cod has the similar apoptotic characteristics as other animals.

Vascular endothelial growth factor polymorphisms are associated with osteosarcoma susceptibility.

Polymorphisms in the vascular endothelial growth factor (VEGF) gene may contribute to osteosarcoma risk, but the results of previous studies have been inconsistent and inconclusive. We conducted a meta-analysis to assess this association more accurately. Relevant studies were collected systemically from three online English databases. Crude odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the associations of three VEGF gene polymorphisms (+936C/T, -634 G/C, +1612 G/A) with osteosarcoma risk. Seven case-control studies involving 1,350 cases and 1,706 controls were selected for the meta-analysis. The pooled OR indicated that the VEGF +936C/T polymorphism was associated with increased risk of osteosarcoma in a Chinese population (T vs. C: OR = 1.26, 95% CI = 1.12-1.42, P < 0.01; TT vs. CC: OR = 1.70, 95% CI = 1.29-2.24, P < 0.01; CT + TT vs. CC: OR = 1.23, 95% CI = 1.06-1.44, P < 0.01; TT vs. CC + CT: OR = 1.61, 95% CI = 1.23-2.10, P < 0.01). A significant association was also found between the -634 G/C polymorphism and osteosarcoma risk (C vs. G: OR = 0.81, 95% CI = 0.69-0.96, P = 0.01; CC vs. GG: OR = 0.66, 95% CI = 0.48-0.90, P < 0.01; GC + CC vs. GG: OR = 0.80, 95% CI = 0.67-0.96, P = 0.02; CC vs. GG + GC: OR = 0.72, 95% CI = 0.60-0.86, P < 0.01). In sum, our meta-analysis suggests VEGF polymorphisms are associated with osteosarcoma susceptibility in the Chinese population. However, further studies that include different ethnicities and larger populations are needed.

Reduced Lateral Root Branching Density Improves Drought Tolerance in Maize.

An emerging paradigm is that root traits that reduce the metabolic costs of soil exploration improve the acquisition of limiting soil resources. Here, we test the hypothesis that reduced lateral root branching density will improve drought tolerance in maize (Zea mays) by reducing the metabolic costs of soil exploration, permitting greater axial root elongation, greater rooting depth, and thereby greater water acquisition from drying soil. Maize recombinant inbred lines with contrasting lateral root number and length (few but long [FL] and many but short [MS]) were grown under water stress in greenhouse mesocosms, in field rainout shelters, and in a second field environment with natural drought. Under water stress in mesocosms, lines with the FL phenotype had substantially less lateral root respiration per unit of axial root length, deeper rooting, greater leaf relative water content, greater stomatal conductance, and 50% greater shoot biomass than lines with the MS phenotype. Under water stress in the two field sites, lines with the FL phenotype had deeper rooting, much lighter stem water isotopic signature, signifying deeper water capture, 51% to 67% greater shoot biomass at flowering, and 144% greater yield than lines with the MS phenotype. These results entirely support the hypothesis that reduced lateral root branching density improves drought tolerance. The FL lateral root phenotype merits consideration as a selection target to improve the drought tolerance of maize and possibly other cereal crops.

Reduced frequency of lateral root branching improves N capture from low-N soils in maize.

Suboptimal nitrogen (N) availability is a primary constraint for crop production in developing countries, while in developed countries, intensive N fertilization is a primary economic, energy, and environmental cost for crop production. We tested the hypothesis that under low-N conditions, maize (Zea mays) lines with few but long (FL) lateral roots would have greater axial root elongation, deeper rooting, and greater N acquisition than lines with many but short (MS) lateral roots. Maize recombinant inbred lines contrasting in lateral root number and length were grown with adequate and suboptimal N in greenhouse mesocosms and in the field in the USA and South Africa (SA). In low-N mesocosms, the FL phenotype had substantially reduced root respiration and greater rooting depth than the MS phenotype. In low-N fields in the USA and SA, the FL phenotype had greater rooting depth, shoot N content, leaf photosynthesis, and shoot biomass than the MS phenotype. The FL phenotype yielded 31.5% more than the MS phenotype under low N in the USA. Our results are consistent with the hypothesis that sparse but long lateral roots improve N capture from low-N soils. These results with maize probably pertain to other species. The FL lateral root phenotype merits consideration as a selection target for greater crop N efficiency.

Is the inherent potential of maize roots efficient for soil phosphorus acquisition?

Sustainable agriculture requires improved phosphorus (P) management to reduce the overreliance on P fertilization. Despite intensive research of root adaptive mechanisms for improving P acquisition, the inherent potential of roots for efficient P acquisition remains unfulfilled, especially in intensive agriculture, while current P management generally focuses on agronomic and environmental concerns. Here, we investigated how levels of soil P affect the inherent potential of maize (Zea mays L.) roots to obtain P from soil. Responses of root morphology, arbuscular mycorrhizal colonization, and phosphate transporters were characterized and related to agronomic traits in pot and field experiments with soil P supply from deficiency to excess. Critical soil Olsen-P level for maize growth approximated 3.2 mg kg(-1), and the threshold indicating a significant environmental risk was about 15 mg kg(-1), which represented the lower and upper levels of soil P recommended in current P management. However, most root adaptations involved with P acquisition were triggered when soil Olsen-P was below 10 mg kg(-1), indicating a threshold for maximum root inherent potential. Therefore, to maintain efficient inherent potential of roots for P acquisition, we suggest that the target upper level of soil P in intensive agriculture should be reduced from the environmental risk threshold to the point maximizing the inherent potential of roots.

[Effects of the leachate recirculation with pH adjusted on anaerobic landfill].

The landfill gas, biochemical indications of leachate and toxicity of leachate had been investigated in two simulated anaerobic bioreactors. After 40 days of simulated rainfall, one reactor was recharged with the original leachate directly while the other one was recharged with the adjusted leachate of which the pH was changed to 7.5. The results indicate that during the simulated rainfall the garbage is acidified rapidly with the pH value decreased to 5.21. Recharged with the original leachate, acidification of the landfill layer is deteriorated. Recirculation of the adjusted leachate, which can produce methane rapidly, can also remove organic pollutants significantly. At the 80th day methane production rate is up to 64.8%. After 170 days, the removal of BOD5 comes to 93.5% while the removal of COD is 89.1%. Furthermore, the biological toxicity of leachate decreases significantly and the semi-lethal concentration of leachate to tetrahymena rises to 3.27% from 0.24% within 24 hours.