Genome-Wide Characterization and Functional Analysis of ABCG Subfamily Reveal Its Role in Cutin Formation in Cotton.

ATP-binding cassette transporter G (ABCG) has been shown to be engaged in export of broad-spectrum compounds with structural differences, but little is known concerning its role in cutin formation of cotton (Gossypium spp.). In this study, we conduct a genome-wide survey and detected 69, 71, 124 and 131 ABCG genes within G. arboretum, G. raimondii, G. hirsutum and G. barbadense, separately. The above ABCGs could be divided into four groups (Ia, Ib, Ic, II). Some ABCG genes such as GhABCG15, whose homologous gene transports cuticular lipid in Arabidopsis, was preferentially expressed in the development of fiber. A weighted gene co-expression network analysis (WGCNA) demonstrated that GhABCG expression was significantly associated with the amount of 16-Hydroxypalmitate (a main component of cutin precursor) in cotton fibers. Further, silencing of GhABCG15 by virus-induced gene silencing (VIGS) in cotton generated brightened and crinkled leaves as well as reduced thickness of cuticle and increased permeability. Chemical composition analysis showed the cutin content in GhABCG15-silenced leaves had decreased while the wax content had increased. Our results provide an insight for better understanding of the role of the Gossypium ABCG family and revealed the essential role of GhABCGs in cotton cutin formation.

Fast extraction of aflatoxins, ochratoxins and enniatins from maize with magnetic covalent organic framework prior to HPLC-MS/MS detection.

A simple, rapid and sensitive vortex-assisted magnetic solid phase extraction (MSPE) method using core-shell structured magnetic covalent organic frameworks (Fe3O4/COF-TpBD) as adsorbents was established for simultaneous determination of aflatoxins, ochratoxins and enniatins in maize before high-performance chromatography tandem spectrometry detection. Fe3O4/COF-TpBD was facilely fabricated, characterized, and applied for simultaneous extraction of ten mycotoxins from maize. Key parameters affecting MSPE efficiency were investigated. The method possessed good linearity (0.05-50 µg/kg), high sensitivity (0.02-1.67 µg/kg for limits of detection), and satisfactory recoveries (73.8-105.3 %), with relative standard deviations less than 8.5 %. The amount of adsorbent used (5 mg) and the time required (0.5 min each for adsorption and for desorption) for MSPE were greatly shortened in comparison with the previous reports. Therefore, the fabricated Fe3O4/COF-TpBD exhibited a great potential for rapid extraction of common mycotoxins in maize, which can be attributed to its multiple interactions with the target mycotoxins.

Facile synthesis and evaluation of three magnetic 1,3,5-triformylphloroglucinol based covalent organic polymers as adsorbents for high efficient extraction of phthalate esters from plastic packaged foods.

Three covalent organic polymers (COPs) were successfully fabricated by room-temperature solvent-free mechanochemical grinding method between 1,3,5-triformylphloroglucinol (TP) and p-phenyl enediamine (COP1), benzidine (COP2), 4, 4″-diamino-p-terphenyl (COP3), and followed by coprecipitation on the surface of Fe3O4 nanoparticles to form three corresponding magnetic Tp-series COPs. The fabricated magnetic COPs were evaluated and then applied for the extraction of phthalate esters from food samples before gas chromatography-tandem spectrometry analysis. Magnetic COP2 exhibited the highest extraction efficiency, which can be attributed to its larger pore size, and its strong hydrophobic and π-π interactions with phthalate esters. The method possessed good linearity (10-1000 µg·kg-1), high sensitivity (0.29-2.59 µg·kg-1 for LODs and 0.97-8.63 µg·kg-1 for LOQs), and satisfactory recoveries (70.2-108.1%) with relative standard deviations lower than 5.2%. This method has potentials for high efficient separation/preconcentration of hydrophobic phthalate esters from foods.

Fabrication of magnetic covalent organic framework for efficient extraction and determination of phthalate esters in milk samples.

Using two monomers of 4,4″-diamino-p-terphenyl and 1,3,5-triformylphloroglucinol, a co-precipitation structured magnetic covalent organic framework adsorbent was fabricated. After that, a high efficient vortex-assisted magnetic solid-phase extraction method was developed prior to gas chromatography-tandem mass spectrometry analysis for the determination of phthalate esters in milk samples. The fabricated magnetic adsorbent was facilely fabricated, fully characterized, and exhibited high extraction efficiency, which can be attributed to its larger pore size as well as strong hydrophobic and π-π stacking interactions between adsorbent and phthalate esters. Key parameters affecting extraction efficiency were investigated. Under the optimized conditions, the proposed method possessed good linearity (3.0-1000 µg/L), high sensitivity (0.8-2.1 µg/L for limits of detection), and satisfactory recoveries (76.8-99.2%). The relative standard deviations for intra-day was 3.1-4.5% and inter-day was 3.3-6.1%. This work is suitable for high efficient separation/preconcentration of phthalate esters in milk samples.

Genome-wide analysis of PRR gene family uncovers their roles in circadian rhythmic changes and response to drought stress in Gossypium hirsutum L.

BACKGROUND: The circadian clock not only participates in regulating various stages of plant growth, development and metabolism, but confers plant environmental adaptability to stress such as drought. Pseudo-Response Regulators (PRRs) are important component of the central oscillator (the core of circadian clock) and play a significant role in plant photoperiod pathway. However, no systematical study about this gene family has been performed in cotton. METHODS: PRR genes were identified in diploid and tetraploid cotton using bioinformatics methods to investigate their homology, duplication and evolution relationship. Differential gene expression, KEGG enrichment analysis and qRT-PCR were conducted to analyze PRR gene expression patterns under diurnal changes and their response to drought stress. RESULTS: A total of 44 PRR family members were identified in four Gossypium species, with 16 in G. hirsutum, 10 in G. raimondii, and nine in G. barbadense as well as in G. arboreum. Phylogenetic analysis indicated that PRR proteins were divided into five subfamilies and whole genome duplication or segmental duplication contributed to the expansion of Gossypium PRR gene family. Gene structure analysis revealed that members in the same clade are similar, and multiple cis-elements related to light and drought stress response were enriched in the promoters of GhPRR genes. qRT-PCR results showed that GhPRR genes transcripts presented four expression peaks (6 h, 9 h, 12 h, 15 h) during 24 h and form obvious rhythmic expression trend. Transcriptome data with PEG treatment, along with qRT-PCR verification suggested that members of clade III (GhPRR5a, b, d) and clade V (GhPRR3a and GhPRR3c) may be involved in drought response. This study provides an insight into understanding the function of PRR genes in circadian rhythm and in response to drought stress in cotton.

Different MicroRNA Families Involved in Regulating High Temperature Stress Response during Cotton (Gossypium hirsutum L.) Anther Development.

MicroRNAs (miRNAs) are small molecule RNAs widely involved in responses to plant abiotic stresses. We performed small RNA sequencing of cotton anthers at four developmental stages under normal and high temperature (NT and HT, respectively) conditions to investigate the stress response characteristics of miRNA to HT. A total of 77 miRNAs, including 33 known miRNAs and 44 novel miRNAs, were identified, and 41 and 28 miRNAs were differentially expressed under NT and HT stress conditions, respectively. The sporogenous cell proliferation (SCP), meiotic phase (MP), microspore release period (MRP), and pollen maturity (PM) stages had 10 (including 12 miRNAs), four (including six miRNAs), four (including five miRNAs), and seven (including 11 miRNAs) HT stress-responsive miRNA families, respectively, which were identified after removing the changes in genotype-specific miRNAs under NT condition. Seven miRNA families (miR2949, miR167, and miR160 at the SCP stage; miR156 and miR172 at the MP stage; miR156 at the MRP stage; and miR393 and miR3476 at the PM stage), which had expression abundance of more than 10% of the total expression abundance, served as the main regulators responding to HT stress with positive or negative regulation patterns. These miRNAs orchestrated the expression of the corresponding target genes and led to different responses in the HT-tolerant and the HT-sensitive lines. The results revealed that the HT stress response of miRNAs in cotton anthers were stage-specific and differed with the development of anthers. Our study may enhance the understanding of the response of miRNAs to HT stress in cotton anthers and may clarify the mechanism of plant tolerance to HT stress.

[Characteristics and Mechanism of Monothioarsenate Adsorption on Sand, Sediment, and Goethite].

Batch experiments were conducted to investigate the adsorption characteristics and mechanism of monothioarsenate (MTA) (>99%) on sand, soil sediment, and goethite under different pH and solid-liquid ratio conditions. Results showed the following. ① When MTA ranged from 0.14 to 23.59, 0.19 to 41.27, and 0.27 to 32.02 mg·L-1 in solutions, its maximum equilibrium adsorption capacity (Qm) in sand, soil sediment, and goethite was 21.54, 277.98, and 2607.42 mg·kg-1, respectively. After its adsorption reached equilibrium, a small amount of the MTA in the solutions transformed into arsenite and arsenate. ② As pH increased from 4 to 10, the equilibrium adsorption capacity (Qe) of MTA on sand decreased gradually, whereas Qe first decreased and then increased for soil sediment and goethite. As the solid-liquid ratio increased, the Qe of MTA in the three media gradually decreased. ③ X-ray powder diffraction (XRD), scanning electron microscope (SEM), and BET results further showed that the major factors controlling MTA adsorption on the three media included the low pore volume of sand, the high degree of crystallization of the soil sediment, and the large number of hydroxyl functional groups (-OH) on goethite.

[Start-up of Simultaneous ANAMMOX and Denitrification Process and Changes in Microbial Community Characteristics].

To understand the relationship between nitrogen and carbon removal performance and the microbial community during start-up of simultaneous ANAMMOX and denitrification (SAD), nitrogen and carbon removal performance and microbial community change were studied by gradually increasing the influent COD concentration. The results showed that with the increase of the influent COD concentration, NH4+-N and NO2--N effluent remained stable, and the average removal rate was more than 98%. The removal rate of TN increased gradually, and the rate was 95.6% in the third stage, which was 6.8% higher than that of ANAMMOX in theory. ΔNO3--N/ΔNH4+-N decreased significantly from 0.15-0.17 to 0.03-0.07. The contribution rate of ANAMMOX to nitrogen removal decreased gradually, denitrification for nitrogen removal increased gradually, and the COD removal rate increased. Sludge activity analysis showed that the denitrification activity of sludge increased significantly and the ANAMMOX activity decreased slightly after the start-up of SAD. High throughput sequencing results showed that the dominant phyla of microorganisms in the reactor were Chloroflexi, Planctomycetes, Firmicutes, Armatimonadetes, and Proteobacteria. The characteristics of the microbial community in the reactor were closely related to the performance of SAD in nitrogen and carbon removal. The main functional microorganisms related to nitrogen and carbon removal were ANAMMOX bacteria, anaerobic digestive bacteria, and denitrifying bacteria. The abundance of ANAMMOX bacteria decreased after the start-up of SAD, and the anaerobic digestive bacteria and heterotrophic denitrifying bacteria increased significantly.

Relaxant effect of flavonoid naringenin on contractile activity of rat colonic smooth muscle.

ETHNOPHARMACOLOGICAL RELEVANCE: Disturbed gastrointestinal (GI) motility can be associated with smooth muscle abnormalities and dysfunction. Exploring innovative approaches that can modulate the disturbed colonic motility are of great importance for clinical therapeutics. Naringenin, a flavonoid presented in many traditional Chinese herbal medicines, has been shown to have a relaxant effect on different smooth muscles. The aim of the present study was to investigate the effect of naringenin on regulation of GI motility. MATERIAL AND METHODS: Mechanical recording was used to investigate the effect of naringenin on isolated rat colonic smooth muscle spontaneous contractions. Whole cell patch clamp, intracellular [Ca(2+)] concentration ([Ca(2+)]i) and membrane potential measurements were examined on primary cultures of colonic smooth muscle cells (SMCs). A neostigmine-stimulated rat model was utilized to investigate the effect of naringenin in vivo. RESULTS: Naringenin induced a concentration-dependent inhibition (1-1000 µM) on rat colonic spontaneous contraction, which was reversible after wash out. The external Ca(2+) influx induced contraction and [Ca(2+)]i increase were inhibited by naringenin (100 µM). In rat colonic SMCs, naringenin-induced membrane potential hyperpolarization was sensitive to TEA and selective large-conductance calcium-activated K(+) (BKCa) channel inhibitor iberiotoxin. Under whole cell patch-clamp condition, naringenin stimulated an iberiotoxin-sensitive BKCa current, which was insensitive to changes in the [Ca(2+)]i concentration. Furthermore, naringenin significantly suppressed neostigmine-enhanced rat colon transit in vivo. CONCLUSION: Our results for the first time demonstrated the relaxant effect of flavonoid naringenin on colon smooth muscle both in vitro and in vivo. The relaxant effect of naringenin was attributed to direct activation of BKCa channels, which subsequently hyperpolarized the colonic SMCs and decreased Ca(2+) influx through VDCC. Naringenin might be of therapeutic value in the treatment of GI motility disorders.

Bifurcations in a low-order nonlinear model of tropical Pacific sea surface temperatures derived from observational data.

Aiming at tackling the difficulty in exactly constituting the sea surface temperature (SST) dynamical model, the paper introduces the dynamical system reconstruction idea and establishes the nonlinear dynamical model of SST field based on 1963-2010 monthly average Hadley SST data. Time coefficients series after empirical orthogonal functions decomposition are taken as the dynamical model variables and Genetic Algorithms is used to optimize and retrieve the model parameters. The stability of the equilibrium in the reconstructed model is analyzed and dynamical actions such as bifurcation and mutation are discussed. Also the activity configuration and aberrance mechanism of the SST field are developed upon the actual activity characteristics of the SST field in the Tropical Pacific Ocean in that year. Results reveal that the bifurcation action of the SST field system from one stable high-value equilibrium to another stable low-value equilibrium accords with the La Niña process while the mutation action of the SST field system from two stable equilibriums to another stable equilibrium accords with the El Niño process.

[Prediction of high temperature harm to rice in Jiangsu Province based on sea surface temperature].

Based on the measurements of rice growth and the ordinary meteorological observations from eight main agro-meteorological stations in Jiangsu Province in 1986-2007, this paper analyzed the characteristics of generation circulation corresponding to the abnormal strong and southern subtropical high pressure in 2003 (the year with a typically high temperature), the relationships between the abnormalities of subtropical high pressure and previous sea surface temperature, and the physiological responses of rice to the abnormal high temperature during its crucial development stages. In the meantime, a field correlation analysis was made on the relationships between the harm index of high temperature in the northern (Huaibei), middle (Jianghuai), and southern (Sunan) areas of Jiangsu and the sea surface temperature (SST) of Western Pacific. The results showed that the harm index of high temperature in the three areas was highly correlated with the SST of Nino area, northern area, and warm pool area of Western Pacific, respectively, but the significance and temporal evolution of the correlations varied among the areas. The transformation of SST was conducted to optimize its correlation with the harm index of high temperature, and an increased reliability of SST acting as a predictor of high temperature harm was obtained. The simulation results of the established models in predicting high temperature harm to rice in Huaibei, Jianghuai and Sunan areas of Jiangsu Province were significant at 0.01 level.

Trimethyltin chloride induced chloride secretion across rat distal colon.

TMT (trimethyltin chloride), an organotin, is ubiquitous in the environment. The consumption of contaminated food may cause exposure of the human diet to this toxic compound. The present study was to investigate the effects of TMT on the regulation of ion transport across the rat distal colon. The rat colonic mucosa was mounted in Ussing chambers. The effects of TMT were assessed using the Isc (short-circuit current). Both apical and basolateral TMT induced, dose-dependently, an increase in Isc, which was due to a stimulation of Cl- secretion as measured using ion substitution experiments and pharmacological manoeuvres. The secretion was also inhibited by several K+ channel blockers administrated at the basolateral side. When the apical side was permeabilized by nystatin, the TMT-induced K+ conductance was effectively blocked by tetrapentylammonium, a Ca2+-sensitive K+ channel blocker. The response of TMT was sensitive to the basolateral Ca2+ and the intracellular Ca2+ store, which could be disclosed by applying the inhibitors of ryanodine receptors and inositol 1,4,5-trisphosphate receptors. In conclusion, TMT led to Cl- secretion, which was essentially regulated by basolateral Ca2+-sensitive K+ channels. These results suggest the importance of K+ channels in the toxicity hazard of TMT.

Cellular mechanisms underlying the laxative effect of flavonol naringenin on rat constipation model.

BACKGROUND & AIMS: Symptoms of constipation are extremely common, especially in the elderly. The present study aim to identify an efficacious treatment strategy for constipation by evaluating the secretion-promoting and laxative effect of a herbal compound, naringenin, on intestinal epithelial anion secretion and a rat constipation model, respectively. METHODS/PRINCIPAL FINDINGS: In isolated rat colonic crypts, mucosal addition of naringenin (100 microM) elicited a concentration-dependent and sustained increase in the short-circuit current (I(SC)), which could be inhibited in Cl- free solution or by bumetanide and DPC (diphenylamine-2-carboxylic acid), but not by DIDS (4, 4'- diisothiocyanatostilbene-2, 2'-disulfonic acid). Naringenin could increase intracellular cAMP content and PKA activity, consisted with that MDL-12330A (N-(Cis-2-phenyl-cyclopentyl) azacyclotridecan-2-imine-hydrochloride) pretreatment reduced the naringenin-induced I(SC). In addition, significant inhibition of the naringenin-induced I(SC) by quinidine indicated that basolateral K+ channels were involved in maintaining this cAMP-dependent Cl- secretion. Naringenin-evoked whole cell current which exhibited a linear I-V relationship and time-and voltage- independent characteristics was inhibited by DPC, indicating that the cAMP activated Cl- conductance most likely CFTR (cystic fibrosis transmembrane conductance regulator) was involved. In rat constipation model, administration of naringenin restored the level of fecal output, water content and mucus secretion compared to loperamide-administrated group. CONCLUSIONS: Taken together, our data suggest that naringenin could stimulate Cl- secretion in colonic epithelium via a signaling pathway involving cAMP and PKA, hence provide an osmotic force for subsequent colonic fluid secretion by which the laxative effect observed in the rat constipation model. Naringenin appears to be a novel alternative treatment strategy for constipation.

Cellular mechanism of adrenalin stimulated chloride secretion via beta-adrenoceptor in T84 cells.

In the present study, the intracellular regulatory pathways involved in the adrenalin-stimulated chloride secretion across T84 cells were investigated. Biphasic characteristics were observed in the Isc response to the basolateral addition of adrenalin (0.25 nM-100 microM). The biphasic response was almost abolished by removing ambient Cl(-). Chloride secretion was found to depend on the activities of basolaterally located Na+-K+-2Cl(-) cotransporters and K+ channels. The alpha-adrenoceptor antagonist phentolamine did not have any effect on either phase of adrenalin-induced Isc, while after pretreatment of the beta-adrenoceptor antagonist propranolol, the adrenalin-induced Isc was substantially abolished, suggesting the biphasic response may be mediated by the beta-adrenoceptor. Under whole cell patch-clamp conditions, T84 cells responded to adrenalin with a rise in inward current. The current, which exhibited a linear I-V relationship and time- and voltage-independent characteristics, was inhibited by the chloride channel blocker DPC and the reverse potential was close to the equilibrium potential for Cl(-) (0 mV), implying that the current was Cl(-) selective. When preloaded with a Ca2+-chelating agent, BAPTA/AM did not affect the Isc response to adrenalin, whereas the Isc was destroyed by pretreating the cells with an adenyl cyclase inhibitor, MDL12330A. These observations were further supported by the intracellular [cAMP] measurement experiment, indicating that adrenalin induced chloride secretion could be mediated by a beta-adrenoceptor only involving cAMP as an intracellular second messenger.