Preparation of cathode catalysts for efficient direct lignin fuel cells by nitrogen doping reduction of oxidized graphene with phthalocyanine iron and Kraft lignin.

Direct lignin fuel cells (DLFC) are one of the important forms of high value-added utilization of lignin. In this study, lignin was studied not only as a fuel but also as a catalyst. Specifically, Kraft lignin was modified with ZnCl2, KOH and THF (Tetrahydrofuran) respectively, and added to the catalyst after activation. The results of scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive spectrometer (EDS), Brunauer - Emmett - Teller (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FT-IR) and Raman spectra shown that AL/FePc-NrGO (activated lignin/iron phthalocyanine/nitrogen-doped reduction of graphene oxide) three-dimensional composite catalyst has been synthesized. The results showed that KOH-activated Kraft lignin had the best performance as an oxygen reduction reaction (ORR) catalyst, with a half-wave potential (E1/2) of 0.73 V and a limiting diffusion current density of 4.3 mA cm-1. The THF-modified catalyst showed similar stability and methanol resistance to 20 % Pt/C at ORR. The ORR catalyst applied to the DLFC has the best electrical performance with an open circuit voltage (OCV) was 0.53 V and the maximum power density it could reach 95.29 mW m-2 when the catalyst was modified with THF. It is encouraging that the AL/FePc-NrGO catalyst has better-generated electricity performance than 20 % Pt/C. This work has provided a new idea for developing non-noble metal catalysts and studying direct biomass liquid fuel cells.

Interaction mechanism of carotenoids and polyphenols in mango peels.

In this study, carotenoids and polyphenols were demonstrated to be the major active substances in the crude pigment extracts (CPE) of mango peels, accounting for 0.26 mg/g and 0.15 mg/g, respectively. The interactions between carotenoids and polyphenols in CPE was observed, as evidenced by that polyphenols significantly improved the antioxidant activity and storage stability of carotenoids in the CPE. Meanwhile, scanning electron microscopy showed that polyphenols are tightly bound to carotenoids. To further elucidate the interaction mechanism, the monomers of carotenoids and polyphenols were identified by HPLC and LC-MS analysis. Lutein (203.85 µg/g), ß-carotene (41.40 µg/g), zeaxanthin (4.20 µg/g) and α-carotene (1.50 µg/g) were authenticated as the primary monomers of carotenoids. Polyphenols were mainly consisted of gallic acid (95.10 µg/g), quercetin-3-ß-glucoside (29.10 µg/g), catechin (11.85 µg/g) and quercetin (11.55 µg/g). The interaction indexes between carotenoid and polyphenol monomer of CPE were calculated. The result indicated that lutein and gallic acid showed the greatest synergistic effect on the scavenging of DPPH and ABTS radical, suggesting the interaction between carotenoids and polyphenols in CPE was mainly caused by lutein and gallic acid. Molecular dynamics simulations and thermodynamic parameters analysis demonstrated that hydrogen bonding, electrostatic interactions, and van der Waals forces played dominant roles in the interaction between lutein and gallic acid, which was confirmed by Raman and X-ray diffraction. These results provided a new perspective on the interaction mechanism between carotenoids and polyphenols, which offered a novel strategy for the enhancement of the activities and stability of bioactive substances.

Evolution and natural selection of ribosome-inactivating proteins in bacteria, fungi, and plants.

Ribosome-inactivating proteins (RIPs) are found in bacteria, fungi, and plants, with a wide range of biological resistances such as anti-fungal, anti-viral, anti-insect, and anti-tumor. They can be roughly divided into proactive defense bacterial or fungal types and passive defense plant types. We identified 1592 RIP genes in bacteria, fungi, and plants. Approximately 88 % of the 764 bacterial RIPs were Shiga or Shiga-like toxins which were exotoxins and could rapidly enter cells to possess strong biotoxicity, and about 98 % of fungal RIPs were predicted as secreted proteins. RIPs were not detected in non-seed plants such as algae, bryophytes, and ferns. However, we found RIPs in some flowering and non-flowering seed plants. The existence of plant RIPs might be related to the structure of seeds or fruits, which might be associated with whether seeds are easy to survive and spread. The evolutionary characteristics of RIPs were different between dicotyledons and monocotyledons. In addition, we also found that RIP2 genes might emerge very early and be plant-specific. Some plant RIP1 genes might evolve from RIP2 genes. This study provides new insights into the evolution of RIPs.

A novel Ag2O-TiO2-Bi2WO6/polyvinyl alcohol composite film with ethylene photocatalytic degradation performance towards banana preservation.

In this research, the Ag2O-TiO2-Bi2WO6(ATB) ternary heterojunction photocatalyst was synthesized by hydrothermal and surface deposition method, and the ATB/PVA composite film with ethylene photocatalytic degradation performance was constructed by the casting method. The structure and properties of ATB and ATB/PVA films were characterized and applied to banana preservation. The results showed that the addition of ATB could improve the mechanical properties, thermal stability, oxygen and moisture resistance, and reduce the crystallinity and light transmittance of PVA films. Compared with TiO2, Bi2WO6 and TB photocatalysts, ATB had the best photocatalytic degradation effect of ethylene under LED light. Compared with blank group, the ethylene concentration decreased by 17.17%. This was mainly attributed to the formation of heterostructure among Ag2O, TiO2 and Bi2WO6, which promoted the separation and transfer of photogenerated carriers. The ATB/PVA composite coating could effectively prevent the respiration of the bananas by inhibiting gas exchange and degrading ethylene, which reduced the weight loss, inhibited glycogen decomposition, improved the pulp hardness, increased titratable acid content, reduced the PPO activity, hindered the phenol oxidation and keep better apparent color of bananas. The safety study suggested that the ATB/PVA film is safe for bananas packaging application.

Genome-wide identification and analysis of Oleosin gene family in four cotton species and its involvement in oil accumulation and germination.

BACKGROUND: Cotton is not only a major textile fiber crop but also a vital oilseed, industrial, and forage crop. Oleosins are the structural proteins of oil bodies, influencing their size and the oil content in seeds. In addition, the degradation of oleosins is involved in the mobilization of lipid and oil bodies during seed germination. However, comprehensive identification and the systematic analysis of the Oleosin gene (OLEOs) family have not been conducted in cotton. RESULTS: An in-depth analysis has enabled us to identify 25 and 24 OLEOs in tetraploid cotton species G. hirsutum and G. barbadense, respectively, while 12 and 13 OLEOs were identified in diploid species G. arboreum and G. raimondii, respectively. The 74 OLEOs were further clustered into three lineages according to the phylogenetic tree. Synteny analysis revealed that most of the OLEOs were conserved and that WGD or segmental duplications might drive their expansion. The transmembrane helices in GhOLEO proteins were predicted, and three transmembrane models were summarized, in which two were newly proposed. A total of 24 candidate miRNAs targeting GhOLEOs were predicted. Three highly expressed oil-related OLEOs, GH_A07G0501 (SL), GH_D10G0941 (SH), and GH_D01G1686 (U), were cloned, and their subcellular localization and function were analyzed. Their overexpression in Arabidopsis increased seed oil content and decreased seed germination rates. CONCLUSION: We identified OLEO gene family in four cotton species and performed comparative analyses of their relationships, conserved structure, synteny, and gene duplication. The subcellular localization and function of three highly expressed oil-related OLEOs were detected. These results lay the foundation for further functional characterization of OLEOs and improving seed oil content.

Novel visible light-responsive graphene oxide/Bi2WO6/starch composite membrane for efficient degradation of ethylene.

Graphene oxide/Bi2WO6 (GBW) photocatalyst was synthesized using a hydrothermal and surface deposition method. GBW/starch composite films with different graphene oxide (GO) additions (0, 0.25, 0.5, 0.75, 1 %) were prepared using a casting method. The GBW photocatalyst and composite starch film were characterized using X-ray diffractometry, X-ray photoelectron spectroscopy, Ultraviolet-visible diffuse reflectance spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, synchronous thermal analyzer, and the capacity of photocatalytic degradation of ethylene under visible light was evaluated. The results showed that GBW strengthens the mechanical properties, water vapor resistance and thermal stability of the composite film. Proper introduction of GO can refine lattice size, reduce bandgap and enhance visible light absorption. When the addition of GO was 0.5 %, GBW/starch composite film showed the strongest visible light degradation activity for ethylene, and the rate constant K' was 9.91 × 10-4 min-1, 4.4 times that of pure Bi2WO6. The composite film also had good recycling performance.

Genome-Wide Association Study Identifies Candidate Genes Related to Seed Oil Composition and Protein Content in Gossypium hirsutum L.

Cotton (Gossypium spp.) is a leading natural fiber crop and an important source of vegetable protein and oil for humans and livestock. To investigate the genetic architecture of seed nutrients in upland cotton, a genome-wide association study (GWAS) was conducted in a panel of 196 germplasm resources under three environments using a CottonSNP80K chip of 77,774 loci. Relatively high genetic diversity (average gene diversity being 0.331) and phenotypic variation (coefficient of variation, CV, exceeding 3.9%) were detected in this panel. Correlation analysis revealed that the well-documented negative association between seed protein (PR) and oil may be to some extent attributable to the negative correlation between oleic acid (OA) and PR. Linkage disequilibrium (LD) was unevenly distributed among chromosomes and subgenomes. It ranged from 0.10-0.20 Mb (Chr19) to 5.65-5.75 Mb (Chr25) among the chromosomes and the range of Dt-subgenomes LD decay distances was smaller than At-subgenomes. This panel was divided into two subpopulations based on the information of 41,815 polymorphic single-nucleotide polymorphism (SNP) markers. The mixed linear model considering both Q-matrix and K-matrix [MLM(Q+K)] was employed to estimate the association between the SNP markers and the seed nutrients, considering the false positives caused by population structure and the kinship. A total of 47 SNP markers and 28 candidate quantitative trait loci (QTLs) regions were found to be significantly associated with seven cottonseed nutrients, including protein, total fatty acid, and five main fatty acid compositions. In addition, the candidate genes in these regions were analyzed, which included three genes, Gh_D12G1161, Gh_D12G1162, and Gh_D12G1165 that were most likely involved in the control of cottonseed protein concentration. These results improved our understanding of the genetic control of cottonseed nutrients and provided potential molecular tools to develop cultivars with high protein and improved fatty acid compositions in cotton breeding programs through marker-assisted selection.

Physico-chemical characterization, antioxidant and anticancer activities in vitro of a novel polysaccharide from Melia toosendan Sieb. Et Zucc fruit.

A novel water-soluble polysaccharide pMTPS-3, obtained from Melia toosendan Sieb. Et Zucc fruit by hot-water extraction and ethanol precipitation, was fractionated by DEAE-52 cellulose anion-exchange and Sephadex G-100 gel filtration chromatography. Its primary structural features and molecular weight were characterized by Fourier infrared spectrometry (FTIR), gel permeation chromatography (GPC) and gas chromatography (GC). And the antioxidant activities of pMTPS-3 in vitro were evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay, superoxide radical scavenging assay and hydroxyl radical scavenging assay. The results suggested that pMTPS-3 was a heteropolysaccharide, composed of arabinose, glucose, mannose, and galactose in the molar ratio of 17.3:28.3:41.6:12.6 with molecular weight 26100Da. The purified pMTPS-3 was revealed to have notable scavenging activity against DPPH radical in a concentration-dependent manner and present a moderate inhibition of superoxide radicals with an IC(50) (5.6mg/ml), and potent inhibiting power for hydroxyl radical compared with crude polysaccharide. Further, it exhibited strong inhibition effect in vitro on the growth of human gastric cancer BGC-823 cells. It is strongly evidenced that pMTPS-3 purified from the crude polysaccharides of Melia toosendan Sieb. Et Zucc could be explored as a potential antioxidant and therapeutics.

Structural features of a new heteropolysaccharide from the fruit bodies of Melia azedarach and its effect on cytotoxic activity.

Water-soluble polysaccharides were extracted from the fruit pulps of Melia azedarach and some columns were undertaken to isolate the major polysaccharide (MPS-III). Its structural features were elucidated by IR analysis, carbohydrate analysis, periodate oxidation, Smith degradation, methylation analysis and NMR spectroscopy. Then it was evaluated for the cytotoxic activity in vitro against four human cell lines, using the sulphorhodamine B assay. The data obtained indicated that MPS-III contains a alpha(1-->4) main chain backbone composed of arabinose, mannose in a molar ratio of 1.31:1.0 and has alpha(1-->6) branch structure. And MPS-III showed a strong cytotoxic activity in the BGC-823 cell line.

A microsatellite-based, gene-rich linkage map reveals genome structure, function and evolution in Gossypium.

The mapping of functional genes plays an important role in studies of genome structure, function, and evolution, as well as allowing gene cloning and marker-assisted selection to improve agriculturally important traits. Simple sequence repeats (SSRs) developed from expressed sequence tags (ESTs), EST-SSR (eSSR), can be employed as putative functional marker loci to easily tag corresponding functional genes. In this paper, 2218 eSSRs, 1554 from G. raimondii-derived and 754 from G. hirsutum-derived ESTs, were developed and used to screen polymorphisms to enhance our backbone genetic map in allotetraploid cotton. Of the 1554 G. raimondii-derived eSSRs, 744 eSSRs were able to successfully amplify polymorphisms between our two mapping parents, TM-1 and Hai7124, presenting a polymorphic rate of 47.9%. However, only a 23.9% (159/754) polymorphic rate was produced from G. hirsutum-derived eSSRs. No relationship was observed between the level of polymorphism, motif type, and tissue origin, but the polymorphism appeared to be correlated with repeat type. After integrating these new eSSRs, our enhanced genetic map consists of 1790 loci in 26 linkage groups and covers 3425.8 cM with an average intermarker distance of 1.91 cM. This microsatellite-based, gene-rich linkage map contains 71.96% functional marker loci, of which 87.11% are eSSR loci. There were 132 duplicated loci bridging 13 homeologous At/Dt chromosome pairs. Two reciprocal translocations after polyploidization between A2 and A3, and between A4 and A5, chromosomes were further confirmed. A functional analysis of 975 ESTs producing 1122 eSSR loci tagged in the map revealed that 60% had clear BLASTX hits (<1e(-10)) to the Uniprot database and that 475 were associated mainly with genes belonging to the three major gene ontology categories of biological process, cellular component, and molecular function; many of the ESTs were associated with two or more category functions. The results presented here will provide new insights for future investigations of functional and evolutionary genomics, especially those associated with cotton fiber improvement.

Complete assignment of the chromosomes of Gossypium hirsutum L. by translocation and fluorescence in situ hybridization mapping.

Significant progress has been made in the construction of genetic maps in the tetraploid cotton Gossypium hirsutum. However, six linkage groups (LGs) have still not been assigned to specific chromosomes, which is a hindrance for integrated genetic map construction. In the present research, specific bacterial artificial chromosome (BAC) clones constructed in G. hirsutum acc. TM-1 for these six LGs were identified by screening the BAC library using linkage group-specific simple-sequence repeats markers. These BAC clones were hybridized to ten translocation heterozygotes of G. hirsutum. L as BAC-fluorescence in situ hybridization probes, which allowed us to assign these six LGs A01, A02, A03, D02, D03, and D08 to chromosomes 13, 8, 11, 21, 24, and 19, respectively. Therefore, the 13 homeologous chromosome pairs have been established, and we have proposed a new chromosome nomenclature for tetraploid cotton.

Characteristics, development and mapping of Gossypium hirsutum derived EST-SSRs in allotetraploid cotton.

In order to construct a saturated genetic map and facilitate marker-assisted selection (MAS) breeding, it is necessary to enhance the current reservoir of known molecular markers in Gossypium. Microsatellites or simple sequence repeats (SSRs) occur in expressed sequence tags (EST) in plants. Many ESTs are publicly available now and represent a good tool in developing EST-SSRs. From 13,505 ESTs developed from our two cotton fiber/ovule cDNA libraries constructed for Upland cotton, 966 (7.15%) contained one or more SSRs and from them, 489 EST-SSR primer pairs were developed. Among the EST-SSRs, 59.1% are trinucleotides, followed by dinucleotides (30%), tetranucleotides (6.4%), pentanucleotides (1.8%), and hexanucleotides (2.7%). AT/TA (18.4%) is the most frequent repeat, followed by CTT/GAA (5.3%), AG/TC (5.1%), AGA/TCT (4.9%), AGT/TCA (4.5%), and AAG/TTC (4.5%). One hundred and thirty EST-SSR loci were produced from 114 informative EST-SSR primer pairs, which generated polymorphism between our two mapping parents. Of these, 123 were integrated on our allotetraploid cotton genetic map, based on the cross [(TM-1xHai7124)TM-1]. EST-SSR markers were distributed over 20 chromosomes and 6 linkage groups in the map. These EST-SSR markers can be used in genetic mapping, identification of quantitative trait loci (QTLs), and comparative genomics studies of cotton.

A comparison of genetic maps constructed from haploid and BC1 mapping populations from the same crossing between Gossypium hirsutum L. and Gossypium barbadense L.

Simple sequence repeat (SSR) genetic maps have been separately constructed based on doubled haploid (DH) and (or) haploid and BC1 populations from the same cross between Gossypium hirsutum L. 'TM-1' and Gossypium barbadense L. 'Hai7124'. The BC1 population was produced by pollinating individual plants of the 'TM-1' x 'Hai7124' F1 with 'TM-1', whereas the DH and (or) haploid population developed from the offspring of Vsg x ('TM-1' x 'Hai7124'). Vsg is a virescently marked semigamy line of Gossypium barbadense L. Pima. The BC1 map included 34 linkage groups with an average distance between markers of 9.80 cM (Kosambi, K) and covered 4331.2 cM (K) or approximately 78.7% of the tetraploid cotton genome constructed using 440 SSR and 2 morphological marker genes. Among them, 26 were assigned to 20 chromosomes, 7 to A or D subgenomes, and 1 was unassigned. The haploid map comprised 444 SSR markers mapped to 40 linkage groups with an average distance of 7.35 cM (K) between markers, covering 3262.9 cM (K) or approximately 60.0% of the tetraploid genome. Twenty-nine linkage groups were assigned to all 19 identified chromosomes, 10 to A or D subgenomes, and 1 was unassigned. Fairly good collinearity of marker order was observed along most of the chromosomes or linkage groups. Significant differences in recombination between maps was observed at the chromosomal and genomic level and possible reasons were discussed. Map comparison and combined data provided an essential basis for further mapping of interested genes and QTLs and for studies of diversity, population structure, and phylogeny in Gossypium species.