Tunable composites prepared from graphene oxide and zeolitic imidazolate framework-8 for improved selective isolation of hemoglobin.

The authors report on the preparation of composites made from graphene oxide (GO) and zeolitic imidazolate framework-8 (ZIF-GO), with various fractions of GO. GO acts as the template and as a modulator for the surface properties of the composites. It also improves the selective adsorption of specific proteins, i.e. hemoglobin (Hb) in this case. The adsorption capacity for Hb is as high as 436 mg g-1 when using a composite containing 20% of GO as sorbent, and 95% of specific activity is maintained for the Hb recovered. The sorbent is applied to selectively isolate Hb from human whole blood. Graphical abstract Graphene oxide-zeolitic imidazolate framework-8 composites (ZIF-GO) with varying mass ratios of GO were prepared in order to tune surface properties and to improve the adsorption selectivity toward hemoglobin.

Construction and analysis of antennal cDNA library from rice striped stem borer, Chilo suppressalis (Walker) (Lepidoptera: Pyralidae), and expression profiles of putative odorant-binding protein and chemosensory protein genes.

In this study, we constructed a high-quality cDNA library from the antennae of the Chilo suppressalis (Walker) (Lepidoptera: Pyralidae). A total of 1,235 colonies with inserts greater than 0.7 kb were sequenced and analyzed. Homology searching coupled with bioinformatics analysis identified 15 and 7 cDNA sequences, respectively, encoding putative odorant-binding proteins (OBPs) and chemosensory proteins (CSPs). A phylogenetic tree of CsupCSPs showed that each CsupCSP has orthologs in Manduca sexta and Bombyx mori with strong bootstrapping support. One CSP was either very specific or more related to the CSPs of another species than to conspecific CSP. The expression profiles of the OBPs and CSPs in different tissues were measured by real-time quantitative PCR. The results revealed that of the 11 OBP genes, the transcript levels of CsupOBP1, CsupOBP5, and CsupOBP7 were higher in both male and female antennae than those in other tissues. And CsupCSP7 was highly expressed in both male and female antennae. Based on these results, the possible physiological functions of CsupOBPs and CsupCSPs were discussed.

Identification and characterization of two sensory neuron membrane proteins from Cnaphalocrocis medinalis (Lepidoptera: Pyralidae).

Sensory neuron membrane proteins (SNMPs), which are located on the dendritic membrane of olfactory neurons, were considered as important components involved in pheromone reception in insects. In Drosophila melanogaster, mutants without SNMP are unable to evoke neuronal activities in the presence of pheromone cis-vaccenyl acetate (cVA). So deeply understanding the SNMPs functions may help to develop pheromone-mediated insect pest management tactics. The present study reports the identification and characterization of CmedSNMP1 and CmedSNMP2, two candidate SNMPs in the rice leaffolder, Cnaphalocrocis medinalis, one of the serious rice insect pests in Asia. The comparison of amino acid sequences shows that CmedSNMP1 and CmedSNMP2 are very similar to the previously reported SNMPs isolated from moths such as Ostrinia nubilalis and O. furnacalis, respectively, but the two CmedSNMPs share low identity with each other. The distribution patterns of two CmedSNMPs in different tissues of adult moths were examined using RT-PCR and quantitative real-time PCR. Although the two genes are expressed not only in antennae but also in nonolfactory tissues such as wings, legs, and body; the relative transcription level shows both CmedSNMP1 and CmedSNMP2 are highly enriched in antennae. The dN/dS ratios of the two CmedSNMPs indicate that the two genes are all subject to purifying selection and evolved to be functional genes. This work presents for the first time a study on the SNMPs of C. medinalis, which may help in providing guidance to future functional research of moth SNMPs.

Preparation of polyhedral oligomeric silsesquioxane based cross-linked inorganic-organic nanohybrid as adsorbent for selective removal of acidic dyes from aqueous solution.

A cross-linked polyhedral oligomeric silsesquioxane (POSS) nanohybrid is synthesized through Schiff base chemistry by using octa-amino POSS as building blocks and glutaraldehyde as dual functional reagent. The obtained nanohybrid is characterized by FT-IR, solid-state 29Si NMR, SEM, TEM, TGA and N2 adsorption-desorption isotherm, and the results demonstrate the successful cross-linkage between POSS molecules, forming block-like irregular nanoparticles with a specific surface area of 42.8m2g-1. As a novel solid-phase adsorbent, cross-linked POSS nanohybrid exhibits selective adsorption properties for acidic dyes, i.e., methyl orange (MO) in the present case. The strong electrostatic interactions between MO species and the nanohybrid are the main driving forces for MO adsorption. The kinetic data are well described by the pseudo-second-order kinetic model. The adsorption isotherm studies demonstrate that the data are well fit with Langmuir model at 293K and a maximum adsorption capacity of 237.5mgg-1 is obtained. Thermodynamic studies indicate that the adsorption of MO is spontaneous and exothermal, along with reduced randomness. The adsorbed MO species could be effectively recovered by using methanol/NaOH (9/1, v/v, 0.1molL-1 NaOH) as eluent. The practical application for textile wastewater treatment demonstrates that cross-linked POSS nanohybrid appears to be a promising material in dye removal field.

RNA interference of NADPH-cytochrome P450 reductase of the rice brown planthopper, Nilaparvata lugens, increases susceptibility to insecticides.

BACKGROUND: NADPH-cytochrome P450 reductase (CPR) is essential for numerous biological reactions catalysed by microsomal cytochrome P450 monooxygenases (P450s). Knockdown of CPR in several insects leads to developmental defects and increased susceptibility to insecticides. However, information about the role of CPR in the brown planthopper, Nilaparvata lugens, is still unavailable. RESULTS: A full-length cDNA encoding CPR was cloned from N. lugens (NlCPR). The deduced amino acid sequence showed marked features of classical CPRs, such as an N-terminus membrane anchor, conserved domains for flavin mononucleotide, flavin adenine dinucleotide (FAD) and nicotinamide adenine dinucleotide phosphate binding, as well as an FAD-binding motif and catalytic residues. Phylogenetic analysis revealed that NlCPR was located in a branch along with bed bug and pea aphid hemipteran insects. NlCPR mRNA was detectable in all tissues and developmental stages of N. lugens, as determined by real-time quantitative PCR. NlCPR transcripts were most abundant in the abdomen in adults, and in first-instar nymphs. Injection of N. lugens with double-strand RNA (dsRNA) against NlCPR significantly reduced the transcription level of the mRNA, and silencing of NlCPR resulted in increased susceptibility in N. lugens to beta-cypermethrin and imidacloprid. CONCLUSION: The results provide first evidence that NlCPR contributes to the susceptibility to beta-cypermethrin and imidacloprid in N. lugens.

Cloning, functional characterization, and expression profiles of NADPH-cytochrome P450 reductase gene from the Asiatic rice striped stem borer, Chilo suppressalis (Lepidoptera: Pyralidae).

NADPH-cytochrome P450 reductase (CPR) is one of the most important components of the cytochrome P450 enzyme system. It catalyzes electron transfer from NADPH to all known P450s, thus plays central roles not only in the metabolism of exogenous xenobiotics but also in the regulation of endogenous hormones in insects. In this study, a full-length cDNA encoding of a CPR (named CsCPR) was isolated from the Asiatic rice striped stem borer, Chilo suppressalis, by using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) methods. The cDNA contains a 2061 bp open reading frame, which encodes an enzyme of 686 amino acid residues, with a calculated molecular mass of 77.6 kDa. The deduced peptide has hallmarks of typical CPR, including an N-terminal membrane anchor and the FMN, FAD and NADPH binding domains. The N-terminal-truncated protein fused with a 6 × His·tag was heterologously expressed in Escherichia coli Rosetta (DE3) cells and purified, specific activity and the Km values of the recombinant enzyme were determined. Tissue- and developmental stage-dependent expression of CsCPR mRNA was investigated by real-time quantitative PCR. The CsCPR mRNA was noticeably expressed in the digestive, metabolic, and olfactory organs of the larvae and adults of C. suppressalis. Our initial results would provide valuable information for further study on the interactions between CPR and cytochrome P450 enzyme systems.

Genomic insights into the glutathione S-transferase gene family of two rice planthoppers, Nilaparvata lugens (Stål) and Sogatella furcifera (Horváth) (Hemiptera: Delphacidae).

BACKGROUND: Glutathione S-transferase (GST) genes control crucial traits for the metabolism of various toxins encountered by insects in host plants and the wider environment, including insecticides. The planthoppers Nilaparvata lugens and Sogatella furcifera are serious specialist pests of rice throughout eastern Asia. Their capacity to rapidly adapt to resistant rice varieties and to develop resistance to various insecticides has led to severe outbreaks over the last decade. METHODOLOGY/PRINCIPAL FINDINGS: Using the genome sequence of N. lugens, we identified for the first time the complete GST gene family of a delphacid insect whilst nine GST gene orthologs were identified from the closely related species S. furcifera. Nilaparvata lugens has 11 GST genes belonging to six cytosolic subclasses and a microsomal class, many fewer than seen in other insects with known genomes. Sigma is the largest GST subclass, and the intron-exon pattern deviates significantly from that of other species. Higher GST gene expression in the N. lugens adult migratory form reflects the higher risk of this life stage in encountering the toxins of non-host plants. After exposure to a sub-lethal dose of four insecticides, chlorpyrifos, imidacloprid, buprofezin or beta-cypermethrin, more GST genes were upregulated in S. furcifera than in N. lugens. RNA interference targeting two N. lugens GST genes, NlGSTe1 and NlGSTm2, significantly increased the sensitivity of fourth instar nymphs to chlorpyrifos but not to beta-cypermethrin. CONCLUSIONS/SIGNIFICANCE: This study provides the first elucidation of the nature of the GST gene family in a delphacid species, offering new insights into the evolution of metabolic enzyme genes in insects. Further, the use of RNA interference to identify the GST genes induced by insecticides illustrates likely mechanisms for the tolerance of these insects.