A comparison of Mersilene tape versus braided suture in transvaginal cervical cerclage: A retrospective case-control study.

OBJECTIVE: Previous studies have indicated that there is an association between cervical cerclage and type of suture material. However, it is still unclear which suture material can provide the greatest benefit to patients who have undergone cerclage. This study investigated the effect of two different suture materials (Mersilene tape vs braided suture) used for transvaginal cervical cerclage placement on maternal outcomes of women with cervical insufficiency. METHODS: In this retrospective case-control study, 170 women who underwent history-, ultrasound-, or physical examination-indicated transvaginal cervical cerclage were categorized according to suture materials used for cerclage: a total of 96 received Mersilene tape and 74 received braided suture. Study participants received a transvaginal cervical cerclage before 28 weeks and were followed up until delivery to assess pregnancy and neonatal outcomes. The primary outcome was gestational age at delivery. Secondary outcomes included preterm premature rupture of membranes (PPROM), premature rupture of membranes (PROM), chorioamnionitis, neonatal survival rate, and neonatal morbidity. RESULTS: Out of 170 eligible women, 74 (43.5%) received braided suture while 96 (56.5%) received Mersilene tape. Baseline characteristics were similar between the two groups. The group that received braided suture had a lower incidence of gestational age at delivery <37 weeks (29.2% vs 54.2%, P = 0.046), PPROM (9.5% vs 21.9%, P = 0.029) and PROM (17.6% vs 32.3%, P = 0.028) compared to the group that received Mersilene tape. However, there were no significant differences between the two groups in average gestational age at delivery, the rate of gestational age at delivery <24, <28, <32, and < 34 weeks, chorioamnionitis, and neonatal survival rate, as well as neonatal morbidity. CONCLUSION: Compared to Mersilene tape, the utilization of braided suture has been significantly associated with a reduction in the incidence of gestational age at delivery <37 weeks, as well as a decreased risk of PPROM and PROM. However, the use of braided sutures did not result in discernible differences in the rates of chorioamnionitis or adverse neonatal outcomes.

Tumor-repopulating cells evade ferroptosis via PCK2-dependent phospholipid remodeling.

Whether stem-cell-like cancer cells avert ferroptosis to mediate therapy resistance remains unclear. In this study, using a soft fibrin gel culture system, we found that tumor-repopulating cells (TRCs) with stem-cell-like cancer cell characteristics resist chemotherapy and radiotherapy by decreasing ferroptosis sensitivity. Mechanistically, through quantitative mass spectrometry and lipidomic analysis, we determined that mitochondria metabolic kinase PCK2 phosphorylates and activates ACSL4 to drive ferroptosis-associated phospholipid remodeling. TRCs downregulate the PCK2 expression to confer themselves on a structural ferroptosis-resistant state. Notably, in addition to confirming the role of PCK2-pACSL4(T679) in multiple preclinical models, we discovered that higher PCK2 and pACSL4(T679) levels are correlated with better response to chemotherapy and radiotherapy as well as lower distant metastasis in nasopharyngeal carcinoma cohorts.

Microbial mechanisms in nitrogen fertilization: Modulating the re-mobilization of clay mineral-bound cadmium in agricultural soils.

Soil cadmium (Cd) can affect crop growth and food safety, and through the enrichment in the food chain, it ultimately poses a risk to human health. Reducing the re-mobilization of Cd caused by the release of protons and acids by crops and microorganisms after stabilization is one of the significant technical challenges in agricultural activities. This study aimed to investigate the re-mobilization of stabilized Cd within the clay mineral-bound fraction of soil and its subsequent accumulation in crops utilizing nitrogen ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3--N), at 60 and 120 mg kg-1. Furthermore, the study harvested root exudates at various growth stages to assess their direct influence on the re-mobilization of stabilized Cd and to evaluate the indirect effects mediated by soil microorganisms. The results revealed that, in contrast to the NO3--N treatment, the NH4+-N treatment significantly enhanced the conversion of clay mineral-bound Cd in the soil to NH4NO3-extractable Cd. It also amplified the accumulation of Cd in edible amaranth, with concentrations in roots and shoots rising from 1.7-6.0 mg kg-1 to 4.3-9.8 mg kg-1. The introduction of NH4+-N caused a decrease in the pH value of the rhizosphere soil and stimulated the production and secretion organic and amino acids, such as oxalic acid, lactic acid, stearic acid, succinic acid, and l-serine, from the crop roots. Furthermore, compared to NO3--N, the combined interaction of root exudates with NH4+-N has a more pronounced impact on the abundance of microbial genes associated with glycolysis pathway and tricarboxylic acid cycle, such as pkfA, pfkB, sucB, sucC, and sucD. The effects of NH4+-N on crops and microorganisms ultimately result in a significant increase in the re-mobilization of stabilized Cd. However, the simulated experiments showed that microorganisms only contribute to 3.8-6.6 % of the re-mobilization of clay mineral-bound Cd in soil. Therefore, the fundamental strategy to inhibit the re-mobilization of stabilized Cd in vegetable cultivation involves the regulation of proton and organic acid secretion by crops.

Using kin discrimination to construct synthetic microbial communities of Bacillus subtilis strains impacts the growth of black soldier fly larvae.

Using synthetic microbial communities to promote host growth is an effective approach. However, the construction of such communities lacks theoretical guidance. Kin discrimination is an effective means by which strains can recognize themselves from non-self, and construct competitive microbial communities to produce more secondary metabolites. However, the construction of cooperative communities benefits from the widespread use of beneficial microorganisms. We used kin discrimination to construct synthetic communities (SCs) comprising 13 Bacillus subtilis strains from the surface and gut of black soldier fly (BSF) larvae. We assessed larval growth promotion in a pigeon manure system and found that the synthetic community comprising 4 strains (SC 4) had the most profound effect. Genomic analyses of these 4 strains revealed that their complementary functional genes underpinned the robust functionality of the cooperative synthetic community, highlighting the importance of strain diversity. After analyzing the bacterial composition of BSF larvae and the pigeon manure substrate, we observed that SC 4 altered the bacterial abundance in both the larval gut and pigeon manure. This also influenced microbial metabolic functions and co-occurrence network complexity. Kin discrimination facilitates the rapid construction of synthetic communities. The positive effects of SC 4 on larval weight gain resulted from the functional redundancy and complementarity among the strains. Furthermore, SC 4 may enhance larval growth by inducing shifts in the bacterial composition of the larval gut and pigeon manure. This elucidated how the SC promoted larval growth by regulating bacterial composition and provided theoretical guidance for the construction of SCs.

Inoculation of Escherichia coli enriched the key functional bacteria that intensified cadmium accumulation by halophyte Suaeda salsa in saline soils.

The enhancement of cadmium (Cd) extraction by plants from contaminated soils associated with phosphate-solubilizing bacteria (PSB) has been widely reported, but the underlying mechanism remains scarcely, especially in Cd-contaminated saline soils. In this study, a green fluorescent protein-labeled PSB, the strain E. coli-10527, was observed to be abundantly colonized in the rhizosphere soils and roots of halophyte Suaeda salsa after inoculation in saline soil pot tests. Cd extraction by plants was significantly promoted. The enhanced Cd phytoextraction by E. coli-10527 was not solely dependent on bacterial efficient colonization, but more significantly, relied on the remodeling of rhizosphere microbiota, as confirmed by soil sterilization test. Taxonomic distribution and co-occurrence network analyses suggested that E. coli-10527 strengthened the interactive effects of keystone taxa in the rhizosphere soils, and enriched the key functional bacteria that involved in plant growth promotion and soil Cd mobilization. Seven enriched rhizospheric taxa (Phyllobacterium, Bacillus, Streptomyces mirabilis, Pseudomonas mirabilis, Rhodospirillale, Clostridium, and Agrobacterium) were obtained from 213 isolated strains, and were verified to produce phytohormone and promote soil Cd mobilization. E. coli-10527 and those enriched taxa could assemble as a simplified synthetic community to strengthen Cd phytoextraction through their synergistic interactions. Therefore, the specific microbiota in rhizosphere soils enriched by the inoculated PSB were also the key to intensifying Cd phytoextraction.

Distribution fractions and potential ecological risk assessment of heavy metals in mangrove sediments of the Greater Bay Area.

The restoration of mangrove in coastal wetlands of China has been started since the 1990s. However, various pollutants, especially for heavy metals (HMs), contained in wastewater might present a significant risk to mangrove forests during the restoration. In this study, sediments of five typical mangrove wetlands with varying restoration years and management measures in the Greater Bay Area were collected to evaluate the distribution fractions and potential ecological risk of HMs. Cd (0.2-1.6 mg/kg) was found in high concentrations in the exchangeable fraction (37.8-71.5%), whereas Cu (54.2-94.8 mg/kg), Zn (157.6-332.6 mg/kg), Cr (57.7-113.6 mg/kg), Pb (36.5-89.9 mg/kg), and Ni (29.7-69.5 mg/kg) primarily presented in residual fraction (30.8-91.9%). According to the geo-accumulation index (Igeo) analysis, sediment Cd presented a high level of pollution (3 ≤ Igeo ≤ 4), while Zn and Cu were associated with moderately pollution (1 ≤ Igeo ≤ 2). Besides, high ecological risk of Cd was found in sediments of five mangroves, with risk assessment code (RAC) ranging from 45.9 to 84.2. Redundancy analysis revealed that the content of NO3--N was closely related to that of HMs in sediments and, pH value and NO3--N concentration affected the distribution of HMs geochemical fractions. High concentration of HMs in QA and NS sampling sites was caused by the formerly pollutants discharge, resulting in these sediments still with a higher HM pollution level after the plant of mangrove for a long period. Fortunately, strict drainage standards for industrial activities in Shenzhen significantly availed for decreasing HMs contents in mangrove sediments. Therefore, future works on mangrove conversion and restoration should be linked to the water purification in the GBA.

Comparison of two stitches versus one stitch for emergency cervical cerclage to prevent preterm birth in singleton pregnancies.

OBJECTIVE: To compare the efficacy of two stitches versus one stitch in women with emergency cervical cerclage. METHODS: A retrospective case-control study of 26 women with singleton pregnancies who underwent emergency cervical cerclage before 26 weeks. A comparison was made between patients with two stitches versus one stitch at the time of cervical cerclage placement. The primary outcome was gestational age (GA) at delivery and preterm birth (PTB) before 37, 34, 32, 28, and 24 weeks. RESULTS: Average GA at delivery in the two-stitches group was significantly greater than in the one-stitch group (32.71 ± 5.54 weeks vs 27.99 ± 4.70 weeks, P = 0.028). There were significant decreases in the incidence of spontaneous PTB at <34 weeks and less than 32 weeks in the two-stitches group (P = 0.034; P = 0.013, respectively). The neonatal intensive care unit (NICU) admissions rate and length of stay in the NICU in the two-stitches group were significantly reduced (P = 0.035 and P = 0.018, respectively). However, there was no significant difference in neonatal mortality between the two groups. CONCLUSION: Compared with emergency cervical cerclage placement with one stitch, the procedure with two stitches can prolong the pregnancy and improve the neonatal prognosis more effectively.

Male antiphonal calls and phonotaxis evoked by female courtship calls in the large odorous frog (Odorrana graminea).

Acoustic communication plays a vital role in frog reproduction. In most anuran species, long-distance sound communication is one-way from males to females; during the reproductive season, males produce species-specific advertisement calls to attract gravid females, and females are generally silent but perform phonotactic movements that lead to amplexus. One exception is the concave-eared torrent frog (Odorrana tormota). In this species, females produce courtship calls that elicit antiphonal vocalizations by males, followed by precise phonotactic movements. The large odorous frog O. graminea (previously Odorrana livida) in southern China is subject to the same environmental constraints as O. tormota, with which it is sympatric; it is unclear whether their sound communication is one-way or bidirectional. Here, we provide the first data on female O. graminea vocalizations and their functions. Using playbacks of female calls, we conducted acoustic behavioral experiments in the laboratory in response to which males emitted single- or multi-note antiphonal calls with a varying fundamental frequency. Moreover, they were attracted to female call playbacks, exhibiting precise phonotaxis. The female courtship call-male response interaction thus forms a duet between partners of a receptive pair. These results demonstrate that this unique communication system likely reflects an adaptation to an environment in which short-distance communication is at a premium given the high levels of ambient noise.

Adjuvant Apatinib in Nasopharyngeal Carcinoma With Residual Epstein-Barr Virus DNA After Radiation Therapy: A Biomarker-Driven, Phase 2 Trial.

PURPOSE: We previously demonstrated that real-time monitoring of plasma Epstein-Barr virus DNA (EBV DNA) during chemoradiation therapy defined 4 distinct phenotypic clusters of nasopharyngeal carcinoma. In particular, the treatment-resistant group, defined as detectable EBV DNA at the end of radiation therapy, had the worst prognosis and is thought to have minimal residual disease. METHODS AND MATERIALS: This is the first phase 2 trial to use a targeted agent, apatinib (an inhibitor of vascular endothelial growth factor receptor 2 tyrosine kinase), in the treatment-resistant group. Eligible patients had plasma EBV DNA > 0 copies/mL at the end of radiation therapy (±1 week). Patients received apatinib (500 mg, once daily) until disease progression, unacceptable toxicity, or for a maximum of 2 years. The primary endpoint was disease-free survival (DFS). RESULTS: Twenty-five patients were enrolled and 23 patients who received apatinib were included in the analyses. Three-year DFS was 47.8% and overall survival was 73.9%. Patients with plasma vascular endothelial growth factor-A ≤150 pg/mL at 28 days after the initiation of treatment had significantly better 3-year DFS (66.7% vs 14.3%; P = .041) and overall survival (88.9% vs 42.9%; P = .033). The most common adverse event of grade ≥3 was nasopharyngeal necrosis (26%), oral/pharyngeal pain (22%), and hand-foot syndrome (22%). Nineteen patients had serial EBV DNA data. Fourteen patients had plasma EBV DNA clearance (turn to 0), and 5 (36%) of these 14 patients had disease recurrence or death, whereas all 5 patients without EBV DNA clearance had disease recurrence or death (3-year DFS: 64.3% vs 0%; P = .001). CONCLUSIONS: The use of antiangiogenic agents shortly after radiation therapy might increase the risk of necrosis. This approach needs to be avoided until translational and preclinical studies reveal the underlying mechanism of interaction between radiation therapy and antiangiogenic agents.

Rhizobacteria communities reshaped by red mud based passivators is vital for reducing soil Cd accumulation in edible amaranth.

Red mud (RM) was constantly reported to immobilize soil cadmium (Cd) and reduce Cd uptake by crops, but few studies investigated whether and how RM influenced rhizobacteria communities, which was a vital factor determining Cd bioavailability and plant growth. To address this concern, high-throughput sequencing and bioinformatics were used to analyze microbiological mechanisms underlying RM application reducing Cd accumulation in edible amaranth. Based on multiple statistical models (Detrended correspondence analysis, Bray-Curtis, weighted UniFrac, and Phylogenetic tree), this study found that RM reduced Cd content in plants not only through increasing rhizosphere soil pH, but by reshaping rhizobacteria communities. Special taxa (Alphaproteobacteria, Gammaproteobacteria, Actinobacteriota, and Gemmatimonadota) associated with growth promotion, anti-disease ability, and Cd resistance of plants preferentially colonized in the rhizosphere. Moreover, RM distinctly facilitated soil microbes' proliferation and microbial biofilm formation by up-regulating intracellular organic metabolism pathways and down-regulating cell motility metabolic pathways, and these microbial metabolites/microbial biofilm (e.g., organic acid, carbohydrates, proteins, S2-, and PO43-) and microbial cells immobilized rhizosphere soil Cd via the biosorption and chemical chelation. This study revealed an important role of reshaped rhizobacteria communities acting in reducing Cd content in plants after RM application.

Nitrogen fertilizer affects rhizosphere Cd re-mobilization by mediating gene AmALM2 and AmALMT7 expression in edible amaranth roots.

In-situ stabilization of Cd-contaminated farmland is a commonly used remediation technology. Yet, rhizosphere metabolites (e.g., organic acids) during crop cultivation may cause Cd re-mobilization and over-accumulation. Here, we identified four pivotal cytomembrane-localized genes underlying Cd accumulation difference between two contrasting edible amaranth cultivars based on root gene expression profile, studied their subcellular localization and functional characteristics, and then investigated effects of nitrogen fertilizer on their expression and rhizosphere Cd re-mobilization. Results showed that more Cd accumulated by edible amaranth was due to rhizosphere Cd mobilization by mediating high expression of AmALMT2 and AmALMT7 genes, not Cd transporters in roots. This was confirmed by heterologous expression of AmALMT2 and AmALMT7 genes in Arabidopsis thaliana, since they mediated malic, fumaric, succinic, and aspartic acids efflux. Furthermore, nitrogen influencing rhizosphere acidification might be closely associated with organic acids efflux genes. Compared with N-NO3- application, N-NH4+ was massively assimilated into glutamates and oxaloacetates through up-regulating glutamine synthetase and alanine-aspartate-glutamate metabolic pathways, thereby enhancing TCA cycle and organic acids efflux dominated by binary carboxylic acids via up-regulating AmALMT2 and AmALMT7 genes, which finally caused Cd re-mobilization. Therefore, N-NO3--dominated nitrogen retarded rhizosphere Cd re-mobilization via inhibiting organic acids efflux function of AmALMT2 and AmALMT7 proteins.

Biomineralization of Cd2+ and inhibition on rhizobacterial Cd mobilization function by Bacillus Cereus to improve safety of maize grains.

Reducing cadmium (Cd) bioavailability and rhizobacterial Cd mobilization functions in the rhizosphere via the inoculation of screened microbial inoculum is an environmental-friendly strategy to improve safety of crop grains. In this study, Bacillus Cereus, a model Cd resistant strain, was selected to explore its effects on Cd bioavailability and uptake, bacterial metabolic functions related to Cd mobilization. Results indicated that inoculation of Bacillus Cereus in maize roots of sand pot with water-soluble Cd (0.06-0.15 mg/kg) and soil pot with high Cd-contaminated soil (total Cd: 2.33 mg/kg; Cd extracted by NH4NO3: 38.6 µg/kg) could decrease water-soluble Cd ion concentration by 7.7-30.1% and Cd extracted with NH4NO3 solution by 7.8-22.5%, inducing Cd concentrations in maize grains reduced by 10.6-39.9% and 17.4-38.6%, respectively. Even for a single inoculation in soil, Cd concentration in maize grains still satisfy food safety requirements (Cd content: 0.1 mg/kg dry weight) due to its successful colonization on root surface of maize. Bacillus Cereus could enrich more plant growth promotion bacteria (PGPB) and down-regulate the expression of genes related to bacterial motility, membrane transports, carbon and nitrogen metabolism in the rhizosphere soil, decreasing Cd bioavailability in soil. Approximately 80% Cd2+ in media was transferred into intracellular, meanwhile Cd salts (sulfide and/or phosphate) were produced in Bacillus Cereus through biomineralization process. Overall, this study could provide a feasible method for improving safety of maize grains via the inoculation of Bacillus Cereus under Cd pollution.

Mandibular Reconstruction Using Free Fibular Flap Graft Following Excision of Calcifying Epithelial Odontogenic Tumor.

ABSTRACT: The calcifying epithelial odontogenic tumor (CEOT) is a rare benign odontogenic tumor, which usually presents with distension of affected tissues. Radiologically, the lesions are often associated with an unerupted tooth and may have spot calcification shadows. The authors report a case of a CEOT in a 48-year-old male involving the right mandibular jaw bone and mentum soft tissues. The authors performed hemimandibulectomy and enucleation followed by reconstruction of the mandible using a vascularized free fibular flap through a digital surgical technique in order to restore the patient's facial symmetry and prepare the area for functional restorations. The case illustrates who the free fibular flap graft can be used for satisfactory mandibular reconstruction and restoration of the morphology and functions.

Nitrogen fertilizer management affects remobilization of the immobilized cadmium in soil and its accumulation in crop tissues.

Immobilization of soil cadmium (Cd) has been the strategy mostly used in remediation of Cd-contaminated arable soil. However, Cd might be remobilized after the immobilization process through the acid-soluble and complexation effects. Development of agronomic management technologies to prevent soil Cd remobilization after the immobilization process was an important pathway to control the food safety of agricultural products in soils with the immobilized Cd. In this study, the ammonia (NH4+-N) and nitrate (NO3--N) forms with concentrations of 60, 90, and 150 mg-N kg-1 soil were performed for evaluating their effects on Cd remobilization with planted or unplanted treatments and Cd accumulation in tissues of edible amaranth (Liuye). With an initial soil palygorskite-bound fraction Cd concentration of 0.6 mg kg-1, bioavailable Cd in rhizosphere soils and Cd in crop shoots respectively increased from 11.4 to 20.6 µg kg-1 (dry soil weight) and 6.92 to 14.92 mg kg-1 (dry plant weight) in planted NH4+-N treatments, while significantly lower concentrations of bioavailable Cd in rhizosphere soils and Cd in crop tissues were observed with planted NO3--N treatments. Compared with that of planted NO3--N treatments, decreasing pH value (i.e., 7.64 to 7.18) induced by root proton efflux during the absorption of NH4+-N, enhancive organic/amino acid (oxalic acid, lactic acid, L-proline, and so on) secretion from roots, and increasing abundance of bacteria distributed in phyla Proteobacteria, Cyanobacteria, and Bacteroidetes with Cd mobilization ability in rhizosphere soils were the main reasons found in this study for the higher Cd remobilization in soils and Cd accumulation in crop under NH4+-N treatments. Moreover, the direct effect of NH4+-N on remobilization of immobilized Cd by upregulating the expression abundances of genes associated with pyruvate metabolism and amino acids metabolism was more significant than that of NO3--N. In summary, the use of NO3--N as preferred N fertilizer was more efficient to ensure the food safety of agricultural products than that of NH4+-N in Cd-contaminated arable soil after immobilization process.

Biological mechanisms of cadmium accumulation in edible Amaranth (Amaranthus mangostanus L.) cultivars promoted by salinity: A transcriptome analysis.

Strategies to prevent cadmium (Cd) mobilization by crops under salinity conditions differs among distinct genotypes, but the biological mechanisms of Cd accumulation in different genotype crops promoted by salinity have remained scarce. In this study, we investigated the biological mechanisms of Cd accumulation in two quite different amaranth cultivars of low-Cd accumulator Quanhong (QH) and high-Cd accumulator Liuye (LY) in response to salt stress. Transcriptomes analysis was carried out on leaves and roots tissues of LY and QH grown with exchangeable Cd 0.27 mg kg-1 and salinity 3.0 g kg-1 treatment or control conditions, respectively. A total of 3224 differentially expressed genes (DEGs) in LY (1119 in roots, 2105 in leaves) and 848 in QH (207 in roots, 641 in leaves) were identified. Almost in each fold change category (2-25, 25-210, >210), the numbers of DEGs induced by salinity in LY treatments were much more than those in QH treatments, indicating that LY is more salt sensitive. Gene ontology (GO) analysis revealed that salinity stress promoted soil acidification and Cd mobilization in LY treatments through the enhancive expression of genes related to adenine metabolism (84-fold enrichment) and proton pumping ATPase (50-fold enrichment) in roots, and carbohydrate hydrolysis (2.5-fold enrichment) in leaves compared with that of whole genome, respectively. The genes expression of organic acid transporter (ALMT) was promoted by 2.71- to 3.94-fold in roots, facilitating the secretion of organic acids. Salt stress also inhibited the expression of key enzymes related to cell wall biosynthesis in roots, reducing the physical barriers for Cd uptake. All these processes altered in LY were more substantially compared with that of QH, suggesting that salt sensitive cultivars might accumulate more Cd and pose a higher health risk.

Interactive effects between cadmium stabilized by palygorskite and mobilized by siderophores from Pseudomonas fluorescens.

The application of palygorskite (PAL) for potentially toxic trace elements (Cd2+, Ni2+, etc.) remediation in polluted soil can substantially reduce the bioavailability and toxicity of these hazard materials. However, the secretion of organic acids and siderophores by microorganisms might result in the re-mobilization of cadmium (Cd) in PAL-bound forms (PAL-Cd). In this study, the interactive effects between Cd stabilized by PAL and mobilized by siderophores from Pseudomonas fluorescens were performed with four flask-shaking experimental treatments, namely, strain with or without an ability of siderophores production respectively associated with or without PAL-Cd. The GC-MS and UHPLC-MS test methods were used to analyze the concentrations of metabolites. Results showed that the Cd mobilized by strain with siderophores production was 22.1% higher than that of strain without the ability of siderophores production (p < 0.05). The mobilization of Cd in PAL in turn significantly reduced the siderophores production of Pseudomonas fluorescens by 25.1% (p < 0.05). The numbers of metabolites significantly up-regulated and down-regulated were 9 and 22 in strain groups with PAL-Cd addition compared with the groups without PAL-Cd, respectively. Metabolomics analysis revealed that the mobilized Cd affects the signal transduction pathway and primary metabolic processes, reduces the metabolic capacity of pentose phosphate pathway, glycolysis and tricarboxylic acid cycle pathway. These changes inhibit the ability of strain to biosynthesize amino acids during the mobilization processes, further reducing the capacity of Pseudomonas fluorescens to produce siderophores. This study provides a useful information on how to select soil Cd-stabilizing materials in a targeted manner and how to avoid Cd re-mobilization by siderophores.

Influence of irrigation with microalgae-treated biogas slurry on agronomic trait, nutritional quality, oxidation resistance, and nitrate and heavy metal residues in Chinese cabbage.

Biogas slurry (BS) is a main byproduct of biogas production that is commonly used for agricultural irrigation because of its abundant nutrients and microelements. However, direct application of BS may cause quality decline and nitrate and heavy metal accumulation in crops. To address this issue, a microalgae culture experiment and an irrigation experiment were performed to evaluate the removal efficiencies of nutrients and heavy metals from diluted BS by microalgae Scenedesmus sp. and to investigate the effects of irrigation with microalgae-treated BS (MBS-25, MBS-50, MBS-75, and MBS-100) on nutritional quality, oxidation resistance, and nitrate and heavy metal residues in Chinese cabbage. After 8 days of continuous culture, a ratio of 1/1 for BS/tap water mixture (BS-50) was the optimal proportion for microalgal growth (3.73 g dry cell L-1) and efficient removal of total nitrogen (86.1%), total phosphorus (94.3%), COD (87.5%), Cr (50%), Pb (60.7%), and Cd (59.7%). The pH in MBS-50 medium recovered to the highest level in a shorter period of time and accelerated the gas stripping of ammonia nitrogen and the formation of insoluble phosphate and metals, which partly contributed to the high removal efficiencies. MBS irrigation significantly promoted crop growth; improved nutritional quality, edible taste, and oxidation resistance; and reduced nitrate and heavy metal residues in Chinese cabbage at a large scale. Therefore, microalgae culture was beneficial to reduce negative impacts of BS irrigation in crop growth and agricultural product safety. This study may provide a theoretical basis for the safe utilization of BS waste in agricultural irrigation.

Low root/shoot (R/S) biomass ratio can be an indicator of low cadmium accumulation in the shoot of Chinese flowering cabbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee) cultivars.

Chinese flowering cabbage is a commonly consumed vegetable that accumulates Cd easily from Cd-contaminated soils. Cultivations of low-Cd cultivars are promising strategies for food safety, but low-Cd-accumulating mechanisms are not fully elucidated. To address this issue, 37 cultivars were screened to identify high- and low-Cd cultivars upon exposure to sewage-irrigated garden soil pretreated with different Cd concentrations (1.81, 2.90, and 3.70 mg kg-1dry soil). The results showed that shoot Cd concentrations differed among the cultivars by maximum degrees of 2.67-, 3.71-, and 3.00-fold under control and treatments, respectively. Soil-pot trial and hydroponic trial found no significant difference in Cd and Ca mobilization, uptake, and transport ability by root per weight between high- and low-Cd cultivars. Interestingly, a stable R/S ratio difference among cultivars (p < 0.01) was observed, and the cultivar variation of Cd accumulation in shoots was mainly dependent on their R/S ratios. R/S ratio was also statistically positively associated with Cd and Ca accumulation in high- and low-Cd cultivars (p < 0.05), both in soil and hydroponics culture. This was mainly due to the lower root biomass of low-Cd cultivars resulted in lower total release of root exudates, lower total Cd and Ca mobilization in rhizosphere soil, and lower total Cd and Ca uptake and transport. The higher shoot biomass of low-Cd cultivars also has dilution effects on Cd concentration in shoot. Overall, low R/S ratio may be regarded as a direct and efficient indicator of low Cd accumulation in the shoot of Chinese flowering cabbage. These findings provided the possibilities to screening low-Cd cultivars using their R/S ratio.

Exogenous Glycinebetaine Promotes Soil Cadmium Uptake by Edible Amaranth Grown during Subtropical Hot Season.

Exogenous glycinebetaine treatment is an effective measure for preventing crops from being exposed to drought and high temperature; however, the effects of this approach on the soil Cd uptake and accumulation by crops remain unclear. Pot experiments were conducted in this study to analyze the effect of glycinebetaine on the soil Cd uptake and accumulation by edible amaranth cultivated in Cd-contaminated soil. Results revealed that after exogenous glycinebetaine treatment on amaranth leaves during the vigorous growth period, the plant biomass, the Cd concentrations in the roots and shoots, and the Cd translocation factor (TF) were significantly higher than those of the control group. The highest Cd concentrations in the roots and shoots and the TF were higher by 91%, 96% and 23.8%, respectively, than the corresponding values in the control group. In addition, exogenous glycinebetaine treatment significantly increased leaf chlorophyll content and promoted the photosynthesis of edible amaranth. Consequently, the contents of soluble sugar, dissolved organic carbon, and low-molecular-weight organic acids significantly increased in the rhizosphere, resulting in Cd mobilization. Significant positive correlations were observed among the contents of leaf chlorophyll, Mg, Fe, pectin and Ca. Given that Cd shares absorption and translocation channels with these elements, we speculated that the increased leaf chlorophyll and pectin contents promoted the absorption and accumulation of Mg, Fe and Ca, which further promoted the absorption and translocation of Cd. These results indicated that exogenous glycinebetaine treatment during hot season would aggravate the health risks of crops grown in Cd-contaminated soils.

Low-Cd tomato cultivars (Solanum lycopersicum L.) screened in non-saline soils also accumulated low Cd, Zn, and Cu in heavy metal-polluted saline soils.

Many reclaimed tidal flat soils feature high salinity and heavy metal (HM) accumulation. Consumption of vegetables cultivated in this type of cropland may cause health risks. Low-Cd tomato cultivars (Solanum lycopersicum L.) were identified in non-saline soil in our previous studies (Tan et al. 2014). However, further research should determine whether these low-Cd cultivars will maintain in the repeatability and stability in saline soil and whether they have low accumulation abilities for accompanying metals (such as Zn and Cu). A soil-pot trial was implemented to measure Cd, Zn, and Cu concentrations in low- and high-Cd cultivars of both common and cherry-type tomatoes grown on HM-polluted reclaimed tidal flat saline soil. Then, cultivar differences in dissolution of Cd, Zn, and Cu in soil and their uptake and redistribution in plants were analyzed. Results showed that the cherry type accumulated more Cd, Zn, and Cu than the common type. Low-Cd cultivars of both types in saline soil accumulated low concentrations of Cd, Zn, and Cu in fruits. Low HM accumulation in fruits is partly attributed to a low root/shoot (R/S) biomass ratio. Low amounts of soil HMs were dissolved because of the low level of rhizosphere organic compounds, which possibly decreased HM uptake by the roots. Low-Cd cultivars of both tomato types had a higher ability to retain HMs in the roots than their high-Cd cultivars. These findings may provide a scientific guidance for the safe cultivation of HM-polluted saline soils.