Enhanced Chromium (VI) Removal by Micron-Scale Zero-Valent Iron Pretreated with Aluminum Chloride under Aerobic Conditions.

Micron-scale zero-valent iron (ZVI)-based material has been applied for hexavalent chromium (Cr(VI)) decontamination in wastewater treatment and groundwater remediation, but the passivation problem has limited its field application. In this study, we combined aluminum chloride solution with ZVI (pcZVI-AlCl3) to enhance Cr(VI) removal behavior under aerobic conditions. The optimal pre-corrosion conditions were found to be 2.5 g/L ZVI, 0.5 mM AlCl3, and a 4 h preconditioning period. Different kinds of techniques were applied to detect the properties of preconditioned ZVI and corrosion products. The 57Fe Mössbauer spectra showed that proportions of ZVI, Fe3O4, and FeOOH in pcZVI-AlCl3 were 49.22%, 34.03%, and 16.76%, respectively. The formation of Al(OH)3 in the corrosion products improved its pHpzc (point of zero charge) for Cr(VI) adsorption. Continuous-flow experiments showed its great potential for Cr(VI) removal in field applications. The ZVI and corrosion products showed a synergistic effect in enhancing electron transfer for Cr(VI) removal. The mechanisms underlying Cr(VI) removal by pcZVI-AlCl3 included adsorption, reduction, and precipitation, and the contribution of adsorption was less. This work provides a new strategy for ZVI pre-corrosion to improve its longevity and enhance Cr(VI) removal.

One-step strategy for efficient Cr(VI) removal via phytate modified zero-valent iron: Accelerated electron transfer and enhanced coordination effect.

The toxic Cr(VI) from industrial wastewater pose serious threat to the human beings and eco-systems. To reduce the operation processes and enhance the removal efficiency of Cr(VI), targeted design of functionalized material is critical in practical applications. Herein, we developed a one-step strategy for simultaneous Cr(VI) reduction and total Cr capture by a novel phytate modified zero-valent iron (PA-ZVI). The reaction kinetics of Cr(VI) removal by PA-ZVI (0.2225 min-1) was 53 times higher compared to ZVI (0.0042 min-1). The Fe(0) content on the surface of PA-ZVI increased from 2.2% to 15.6% compared to ZVI. Meanwhile, Cr(VI) was liable to adsorb on the surface of PA-ZVI due to its lower adsorption energy compared with the original ZVI (-2.09 eV vs -0.85 eV). The incorporation of the phytate ligand promoted electron transfer from iron core to Cr(VI), leading to the rapid in-situ reduction of Cr(VI) adsorbed on the surface of PA-ZVI to Cr(III). PA-ZVI exhibited a satisfactory performance for Cr(VI) removal at a broad pH range (3-11) and in the presence of coexisting ions and humic acid. Moreover, the reactor with the addition of PA-ZVI achieved more than 90% Cr(VI) removal within 72 h in continuous flow experiments. The feasibility of PA-ZVI for the removal of Cr(VI) is also validated in authentic wastewater. This work provides novel ZVI materials that can effectively address decontamination challenges from Cr(VI) pollution.

Horizontally Transferred Salivary Protein Promotes Insect Feeding by Suppressing Ferredoxin-Mediated Plant Defenses.

Herbivorous insects such as whiteflies, planthoppers, and aphids secrete abundant orphan proteins to facilitate feeding. Yet, how these genes are recruited and evolve to mediate plant-insect interaction remains unknown. In this study, we report a horizontal gene transfer (HGT) event from fungi to an ancestor of Aleyrodidae insects approximately 42 to 190 million years ago. BtFTSP1 is a salivary protein that is secreted into host plants during Bemisia tabaci feeding. It targets a defensive ferredoxin 1 in Nicotiana tabacum (NtFD1) and disrupts the NtFD1-NtFD1 interaction in plant cytosol, leading to the degradation of NtFD1 in a ubiquitin-dependent manner. Silencing BtFTSP1 has negative effects on B. tabaci feeding while overexpressing BtFTSP1 in N. tabacum benefits insects and rescues the adverse effect caused by NtFD1 overexpression. The association between BtFTSP1 and NtFD1 is newly evolved after HGT, with the homologous FTSP in its fungal donor failing to interact and destabilize NtFD1. Our study illustrates the important roles of horizontally transferred genes in plant-insect interactions and suggests the potential origin of orphan salivary genes.

The efficient adsorption of tetracycline from aqueous solutions onto polymers with different N-vinylpyrrolidone contents: equilibrium, kinetic and dynamic adsorption.

Extensive use of antibiotics in the world will cause potential risks to human health and ecosystems. The removal of these antibiotics has attracted much attention. Composite materials are growing attention for diverse pollutants separation and removal based on their specific functionality and surface area. In this study, a series of N-vinylpyrrolidone-divinylbenzene polymers (NVPD) with different N-vinylpyrrolidone (NVP) contents were facilely prepared for the adsorption of tetracycline (TC). The effect of polymer surface properties and aqueous solution chemistry (pH, ionic strength, humic acid) on TC adsorption was further studied. The dynamic adsorption and regeneration experiments were also assessed. The results showed that only 25% of NVP was involved in the reaction. When NVP dosage (%) was 75%, polymer (NVPD-g) owned the largest BET surface area (613.23 m2/g) and obtained the maximum TC adsorption capacities (258.76 mg/g). In the kinetic, the adsorption between TC and polymers with NVP was controlled by chemical adsorption and intra-particle diffusion. The TC adsorption process of NVPD-g depended on the contribution of the hydrophobic effect, electrostatic interactions, H-bonding, π-π electron donor-acceptor (EDA) interactions, and cation-π bonding. Moreover, the removal efficiency of TC by NVPD-g was enhanced in the presence of humic acid (HA) in the dynamic adsorption and 1197 BV (2394 mL) of TC simulated wastewater can be treated. These findings suggest that NVPD-g has a potential application in the purification of TC.

The Genetic Network of Forkhead Gene Family in Development of Brown Planthoppers.

We identified 18 distinct Fox genes in the genome of the brown planthopper, Nilaparvata lugens, and further found a novel insect-specific subfamily that we temporarily named FoxT. A total of 16 genes were highly expressed in the eggs, while NlFoxL2 and NlFoxT are female- and male-specific genes, respectively. Large scale RNAi and RNA-seq analyses were used to reveal the functions and potential targets of NlFoxs. In the eggs, NlFoxA, NlFoxN1 and NlFoxN2 are indispensable to early embryogenesis by regulating different target genes; NlFoxG and NlFoxQ co-regulate NlSix3 for brain development; and NlFoxC, NlFoxJ1 and NlFoxP have complementary effects on late embryogenesis. Moreover, NlFoxA, NlFoxNl and NlFoxQ have pleiotropism. NlFoxA and NlFoxQ regulate the expression of NlCHS1 and cuticular proteins, respectively, thereby participating in the formation of cuticles. NlFoxN1, which regulates the expression of NlKrt9 is involved in the formation of intermediate filament frameworks. Our previous studies have revealed that NlFoxL2 and NlFoxO play important roles in chorion formation and wing polyphenism. Altogether, N. lugens Fox genes exhibit functional diversity in embryonic development and organogenesis. This comprehensive study combines genomics, transcriptomics and phenomics, thereby constructing a complex genetic network that spans the entire life cycle of the brown planthopper.

Activation modes in biocatalytic radical cyclization reactions.

Radical cyclizations are essential reactions in the biosynthesis of secondary metabolites and the chemical synthesis of societally valuable molecules. In this review, we highlight the general mechanisms utilized in biocatalytic radical cyclizations. We specifically highlight cytochrome P450 monooxygenases (P450s) involved in the biosynthesis of mycocyclosin and vancomycin, nonheme iron- and α-ketoglutarate-dependent dioxygenases (Fe/αKGDs) used in the biosynthesis of kainic acid, scopolamine, and isopenicillin N, and radical S-adenosylmethionine (SAM) enzymes that facilitate the biosynthesis of oxetanocin A, menaquinone, and F420. Beyond natural mechanisms, we also examine repurposed flavin-dependent "ene"-reductases (ERED) for non-natural radical cyclization. Overall, these general mechanisms underscore the opportunity for enzymes to augment and enhance the synthesis of complex molecules using radical mechanisms.

A digital protein microarray for COVID-19 cytokine storm monitoring.

Despite widespread concern regarding cytokine storms leading to severe morbidity in COVID-19, rapid cytokine assays are not routinely available for monitoring critically ill patients. We report the clinical application of a digital protein microarray platform for rapid multiplex quantification of cytokines from critically ill COVID-19 patients admitted to the intensive care unit (ICU) at the University of Michigan Hospital. The platform comprises two low-cost modules: (i) a semi-automated fluidic dispensing/mixing module that can be operated inside a biosafety cabinet to minimize the exposure of the technician to the virus infection and (ii) a 12-12-15 inch compact fluorescence optical scanner for the potential near-bedside readout. The platform enabled daily cytokine analysis in clinical practice with high sensitivity (<0.4 pg mL-1), inter-assay repeatability (∼10% CV), and rapid operation providing feedback on the progress of therapy within 4 hours. This test allowed us to perform serial monitoring of two critically ill patients with respiratory failure and to support immunomodulatory therapy using the selective cytopheretic device (SCD). We also observed clear interleukin-6 (IL-6) elevations after receiving tocilizumab (IL-6 inhibitor) while significant cytokine profile variability exists across all critically ill COVID-19 patients and to discover a weak correlation between IL-6 to clinical biomarkers, such as ferritin and C-reactive protein (CRP). Our data revealed large subject-to-subject variability in patients' response to COVID-19, reaffirming the need for a personalized strategy guided by rapid cytokine assays.

Salivary DNase II from Laodelphax striatellus acts as an effector that suppresses plant defence.

Extracellular DNA, released by damaged plant cells, acts as a damage-associated molecular pattern (DAMP). We demonstrated previously that the small brown planthopper (Laodelphax striatellus, SBPH) secreted DNase II when feeding on artificial diets. However, the function of DNase II in insect feeding remained elusive. The influences of DNase II on SBPHs and rice plants were investigated by suppressing expression of DNase II or by application of heterogeneously expressed DNase II. We demonstrated that DNase II is mainly expressed in the salivary gland and is responsible for DNA-degrading activity of saliva. Knocking down the expression of DNase II resulted in decreased performance of SBPH reared on rice plants. The dsDNase II-treated SBPH did not influenced jasmonic acid (JA), salicylic acid (SA), ethylene (ET) pathways, but elicited a higher level of H2 O2 and callose accumulation. Application of heterogeneously expressed DNase II in DNase II-deficient saliva slightly reduced the wound-induced defence response. We propose a DNase II-based invading model for SBPH feeding on host plants, and provide a potential target for pest management.

Nickel speciation of spent electroless nickel plating effluent along the typical sequential treatment scheme.

The electroless nickel (EN) industry has suffered from the reduction in Ni concentration to lower than 0.1 mg/L. Hence, Ni speciation along a typical sequential treatment scheme has important implications to optimize the design of advanced treatment. For the first time, we revealed the Ni speciation in segmented EN outfall effluents by virtue of multiple analytical methods. After ensuring all the Ni-bearing complexes were completely dissolved by size-fractioned ultrafiltration trials, customized mass spectra analysis was conducted. In a series of ICP-MS assays, the potential polyatomic interfering species was primarily excluded. The chromatography hyphenated IC-ICP-MS and SEC-ICP-MS results demonstrated that the dominant Ni species in the EN effluents was similar to EDTA-Ni but with a smaller size. The LC-MS experiment further distinguished several typical Ni-bearing complexes. Although Ni concentration declined continuously along the treatment scheme, the number of detected Ni-bearing complexes gradually increased but with lower molecular weights. Most of the detected mononuclear complexes had higher indexes of hydrogen deficiency (IHD) than EDTA-Ni, whereas it was believed that the similar stereo ring shape was widespread in the EN effluent. Considering the efficient Ni decrease after the Fenton unit, further post-treatment approaches featuring higher active radical yields were suggested.

Two insulin receptors determine alternative wing morphs in planthoppers.

Wing polyphenism is an evolutionarily successful feature found in a wide range of insects. Long-winged morphs can fly, which allows them to escape adverse habitats and track changing resources, whereas short-winged morphs are flightless, but usually possess higher fecundity than the winged morphs. Studies on aphids, crickets and planthoppers have revealed that alternative wing morphs develop in response to various environmental cues, and that the response to these cues may be mediated by developmental hormones, although research in this area has yielded equivocal and conflicting results about exactly which hormones are involved. As it stands, the molecular mechanism underlying wing morph determination in insects has remained elusive. Here we show that two insulin receptors in the migratory brown planthopper Nilaparvata lugens, InR1 and InR2, have opposing roles in controlling long wing versus short wing development by regulating the activity of the forkhead transcription factor Foxo. InR1, acting via the phosphatidylinositol-3-OH kinase (PI(3)K)-protein kinase B (Akt) signalling cascade, leads to the long-winged morph if active and the short-winged morph if inactive. InR2, by contrast, functions as a negative regulator of the InR1-PI(3)K-Akt pathway: suppression of InR2 results in development of the long-winged morph. The brain-secreted ligand Ilp3 triggers development of long-winged morphs. Our findings provide the first evidence of a molecular basis for the regulation of wing polyphenism in insects, and they are also the first demonstration--to our knowledge--of binary control over alternative developmental outcomes, and thus deepen our understanding of the development and evolution of phenotypic plasticity.

Nickel-catalyzed Suzuki-Miyaura couplings in green solvents.

The nickel-catalyzed Suzuki-Miyaura coupling of aryl halides and phenol-derived substrates with aryl boronic acids using green solvents, such as 2-Me-THF and tert-amyl alcohol, is reported. This methodology employs the commercially available and air-stable precatalyst, NiCl2(PCy3)2, and gives biaryl products in synthetically useful to excellent yields. Using this protocol, bis(heterocyclic) frameworks can be assembled efficiently.