Behavioral and molecular response of the insect parasitic nematode Steinernema carpocapsae to plant volatiles.

Entomopathogenic nematodes (EPNs) use the chemical cues emitted by insects and insect-damaged plants to locate their hosts. Steinernema carpocapsae, a species of EPN, is an established biocontrol agent used against insect pests. Despite its promising potential, the molecular mechanisms underlying its ability to detect plant volatiles remain poorly understood. In this study, we investigated the response of S. carpocapsae infective juveniles (IJs) to 8 different plant volatiles. Among these, carvone was found to be the most attractive volatile compound. To understand the molecular basis of the response of IJs to carvone, we used RNA-Seq technology to identify gene expression changes in response to carvone treatment. Transcriptome analysis revealed 721 differentially expressed genes (DEGs) between carvone-treated and control groups, with 403 genes being significantly upregulated and 318 genes downregulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the responsive DEGs to carvone attraction were mainly involved in locomotion, localization, behavior, response to stimulus, and olfactory transduction. We also identified four upregulated genes of chemoreceptor and response to stimulus that were involved in the response of IJs to carvone attraction. Our results provide insights into the potential transcriptional mechanisms underlying the response of S. carpocapsae to carvone, which can be utilized to develop environmentally friendly strategies for attracting EPNs.

Investigation on the effect of fluorescence quenching of bovine serum albumin by cefoxitin sodium using fluorescence spectroscopy and synchronous fluorescence spectroscopy.

The reaction mechanism of cefoxitin sodium with bovine serum albumin was investigated using fluorescence spectroscopy and synchronous fluorescence spectroscopy at different temperatures. The results showed that the change of binding constant of the synchronous fluorescence method with increasing temperature could be used to estimate the types of quenching mechanisms of drugs with protein and was consistent with one of fluorescence quenching method. In addition, the number of binding sites, type of interaction force, cooperativity between drug and protein and energy-transfer parameters of cefoxitin sodium and bovine serum albumin obtained from two methods using the same equation were consistent. Electrostatic force played a major role in the conjugation reaction between bovine serum albumin and cefoxitin sodium, and the type of quenching was static quenching. The primary binding site for cefoxitin sodium was sub-hydrophobic domain IIA, and the number of binding sites was 1. The value of Hill's coefficients (nH ) was approximately equal to 1, which suggested no cooperativity in the bovine serum albumin-cefoxitin sodium system. The donor-to-acceptor distance r < 7 nm indicated that static fluorescence quenching of bovine serum albumin by cefoxitin sodium was also a non-radiation energy-transfer process. The results indicated that synchronous fluorescence spectrometry could be used to study the reaction mechanism between drug and protein, and was a useful supplement to the conventional method. Copyright © 2015 John Wiley & Sons, Ltd.

Using resonance light scattering and UV/vis absorption spectroscopy to study the interaction between gliclazide and bovine serum albumin.

At different temperatures (298, 310 and 318 K), the interaction between gliclazide and bovine serum albumin (BSA) was investigated using fluorescence quenching spectroscopy, resonance light scattering spectroscopy and UV/vis absorption spectroscopy. The first method studied changes in the fluorescence of BSA on addition of gliclazide, and the latter two methods studied the spectral change in gliclazide while BSA was being added. The results indicated that the quenching mechanism between BSA and gliclazide was static. The binding constant (Ka ), number of binding sites (n), thermodynamic parameters, binding forces and Hill's coefficient were calculated at three temperatures. Values for the binding constant obtained using resonance light scattering and UV/vis absorption spectroscopy were much greater than those obtained from fluorescence quenching spectroscopy, indicating that methods monitoring gliclazide were more accurate and reasonable. In addition, the results suggest that other residues are involved in the reaction and the mode 'point to surface' existed in the interaction between BSA and gliclazide. Copyright © 2015 John Wiley & Sons, Ltd.

Characteristic Steroids from the South China Sea Gorgonian Muricella sibogae and Their Cytotoxicities.

Twenty-four steroid-based natural products, 9,10-secosteroids (1-10), 1,4-dien-3-one steroids (11-19), and 4-en-3-one steroids (20-24), containing varying side-chains, were isolated from the South China Sea gorgonian Muricella sibogae. The structures of one new 9,10-secosteroid, sibogol D (1), and two new 1,4-dien-3-one steroids, sibogols E and F (11 and 12), were elucidated by extensive spectroscopic analyses and by comparison with the literature data. Cytotoxicities for all the isolates were evaluated against four selected tumor cell lines, HL-60, HCT116, K562, and P388. Compounds 3, 9, and 13 exhibited potent cytotoxic activities against the HL-60 cell line, with IC50 values ranging from 1.27 to 10.05 µM, and compound 3 was also cytotoxic against HCT116 with an IC50 value of 5.8 µM. The bioassay results also indicated a potential relationship between structural patterns and activity. The newly presented series of 1,4-dien-3-one and 4-en-3-one types of steroids relating to the unique 9,10-secosteroids in biogenesis were found in this species for the first time, which is of considerable chemotaxonomic significance.

[The Investigation on the Interaction of Colistin Sulfate with Bovine Serum Albumin with Resonance Light Scattering Spectroscopy].

The interaction between colistin sulfate (CS) with bovine serum albumin in physiological buffer (pH 7.4) was investigated with resonance light scattering spectroscopy at 298, 310, and 318 K. The analysis of data indicated that quenching mechanism of BSA-CS was probably static. The value of n was approximately 1, indicating there was only a single class of binding sites on BSA for CS compounds. The thermodynamic parameters were calculated at different temperatures, implying that the interaction was spontaneous and electrostatic force played major role in the binding between CS and BSA. The values of nH were equal to 1 at different temperatures, indicating there was non-cooperative reaction between BSA and CS. The feasibility of resonance light scattering spectroscopy was verified by fluorescence quenching spectroscopy. The quenching reactive parameters (KSV，Kq，n，Ka) from two methods were similar, suggesting resonance light scattering spectroscopy could be used to study the binding interaction between protein and drugs. Resonance light scattering spectroscopy can be used to explore the substance without intrinsic fluorescence, suggesting that the application of resonance light scattering spectroscopy broadens the understanding of the interaction between small molecules and protein.

Cloning of Two Acetylcholinesterase Genes and Analysis of Point Mutations Putatively Associated with Triazophos Resistance in Chilo auricilius (Lepidoptera: Pyralidae).

Acetylcholinesterase (AChE) is the target of organophosphate (OP) and carbamate insecticides. Mutations in the AChE gene (ace) leading to decreased insecticide susceptibility is the main resistance mechanism in insects. In this study, two Chilo auricilius acetylcholinesterase genes, designated as Caace1 and Caace2, were cloned using RT-PCR and RACE. Caace1 cDNA is 2534 bp, with ORF of 2082 bp, and it encodes an acetylcholinesterase 1 (CaAChE1) protein comprising a calculated 693 amino acid (aa) residues. Caace2 cDNA contains 2280 bp, with a full-length ORF of 1917 bp, encoding acetylcholinesterase 2 (CaAChE2) comprising a calculated 638 aa residues. At the aa level, CaAChE1 displays the highest similarity (97%) with the Chilo suppressalis AChE1, and CaAChE2 shows the highest similarity with the C. suppressalis AChE2 (99%). From the restriction fragment length polymorphism (RFLP) PCR (RFLP-PCR) analysis, one mutation in Caace1, similar to the ace1 mutation associated with triazophos resistance in C. suppressalis, was detected. Detailed examination of field populations of C. auricilius indicated this resistance mutation in C. auricilius is still quite infrequent. Based on the assay of AChE activity and RFLP-PCR testing, an individual that contains resistance mutation has lower AChE activities, while the individual that does not contain the resistance mutation has higher AChE activities. This study provides a basis for future investigations into the mechanism of OP resistance in C. auricilius, as well as a guidance for C. auricilius control with reasonable choice of pesticides.

Molecular characterization of the piggyBac-like element, a candidate marker for phylogenetic research of Chilo suppressalis (Walker) in China.

BACKGROUND: Transposable elements (TEs, transposons) are mobile genetic DNA sequences. TEs can insert copies of themselves into new genomic locations and they have the capacity to multiply. Therefore, TEs have been crucial in the shaping of hosts' current genomes. TEs can be utilized as genetic markers to study population genetic diversity. The rice stem borer Chilo suppressalis Walker is one of the most important insect pests of many subtropical and tropical paddy fields. This insect occurs in all the rice-growing areas in China. This research was carried out in order to find diversity between C. suppressalis field populations and detect the original settlement of C. suppressalis populations based on the piggyBac-like element (PLE). We also aim to provide insights into the evolution of PLEs in C. suppressalis and the phylogeography of C. suppressalis. RESULTS: Here we identify a new piggyBac-like element (PLE) in the rice stem borer Chilo suppressalis Walker, which is called CsuPLE1.1 (GenBank accession no. JX294476). CsuPLE1.1 is transcriptionally active. Additionally, the CsuPLE1.1 sequence varied slightly between field populations, with polymorphic indels (insertion/deletion) and hyper-variable regions including the identification of the 3' region outside the open reading frame (ORF). CsuPLE1.1 insertion frequency varied between field populations. Sequences variation was found between CsuPLE1 copies and varied within and among field populations. Twenty-one different insertion sites for CsuPLE1 copies were identified with at least two insertion loci found in all populations. CONCLUSIONS: Our results indicate that the initial invasion of CsuPLE1 into C. suppressalis occurred before C. suppressalis populations spread throughout China, and suggest that C. suppressalis populations have a common ancestor in China. Additionally, the lower reaches of the Yangtze River are probably the original settlement of C. suppressalis in China. Finally, the CsuPLE1 insertion site appears to be a candidate marker for phylogenetic research of C. suppressalis.

[Modification on the interaction of glipizide with bovine serum albumin by molecular spectroscopy].

In the Tris-HCl buffer solution with pH was 7.40, the interaction between glipizide (Gli) and bovine serum albumin (BSA) was investigated by classical fluorescence spectroscopy with the change of protein as investigation object and elastic scattering fluorescence spectrometry with the change of drugs as investigation object at 293 K and 303 K, the conclusions of the two methods were consistent. Results showed that Gli could quench the intrinsic fluorescence of BSA, and the quenching mechanism was a dynamic quenching process. The hydrophobic force played an important role in the conjugation reaction between BSA and Gli, the binding site mainly located in BSA hydrophobic region and the number of binding site (n) in the binary system was approximately to 1. The values of Hill's coefficients were less than 1, which indicated the weak negative cooperativity in BSA-Gli system. The binding constant (Ka) obtained by elastic scattering fluorescence spectrometric was much larger than the one obtained by classical fluorescence spectroscopy, indiciating that it was more accurate and reasonable when using the change of drug's fluorescence as the research object. At last, the scientificalness of the new method based on elastic scattering fluorescence spectrometric was verified by ultraviolet spectroscopy. The research results showed that there existed insufficiency in analysis of the interaction of drug with protein by classical fluorescence spectroscopy with the change of protein as investigation object, and the fluorescence spectrogram only reflected partial information of the interaction between drug and protein, while the interaction between drug and protein could be better expressed by elastic scattering fluorescence spectrometry with the change of drugs as investigation object.

(E)-ß-Farnesene Protects Rice from Rice Striped Stem Borer Attack by Inhibiting Its Beneficial Gut Microbes.

Herbivores harbor gut microbes that affect their development and contribute to their nutrition, reproduction, and survival. Plant defenses could target the herbivore's beneficial gut microbes, but this has not been well studied in rice. In this context, we identified a rice terpene synthase gene, Os04g0341500. It was strongly induced after feeding by rice striped stem borers (SSB, Chilo suppressalis), and it can catalyze the (E)-ß-farnesene (Eßf) synthesis. When added to artificial diets, Eßf impaired the development and survival of SSB larvae. High-throughput amplicon sequencing revealed that SSB fed on Eßf were decreased in beneficial gut microbes, compared to those feeding on the corresponding control feed. In vitro feeding of Eßf suggested that this antimicrobial sesquiterpene directly inhibited the growth of SSB gut microbes. The present study suggested that the Eßf-induced decrease of relative abundance of gut microbes potentially impairs larval development and survival in SSB.

Interactions between Meteorus pulchricornis and Spodoptera exigua multiple nucleopolyhedrovirus.

Baculoviruses may interact with parasitoids in the same host. A previous study has shown that infection of larvae with Spodoptera litura nucleopolyhedrovirus (SpltNPV) was deleterious to the survival and development of Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae). In this paper, the interactions between M. pulchricornis and Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) in Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), a permissive host of the virus and parasitoid, were investigated. The results showed that the effect of M. pulchricornis on SeMNPV and the effect of the virus on the parasitoid both depended on the concentration of the virus and the interval between viral infection and parasitism. Whether S. exigua was treated with the parasitoid and virus simultaneously or 1 day apart, the biological activities of 10(5), 10(6), and 10(7) OBs/mL SeMNPV were all significantly improved by M. pulchricornis. In contrast, the biological activity of 10(3) OBs/mL SeMNPV was significantly decreased when the host was exposed to the virus and parasitoid simultaneously. Regarding the impact of SeMNPV on M. pulchricornis, exposing the host to the parasitoid and SeMNPV with concentrations lower than 10(6) occlusion bodies (OBs)/mL produced no negative effects on the parasitoid. The results also showed that ingestion of SeMNPV by adult stage M. pulchricornis significantly increased the number of parasitoid offspring that successfully emerged from the host. Furthermore, M. pulchricornis was found to transmit SeMNPV among populations of S. exigua. Taken together, these findings indicate that M. pulchricornis integrated with an appropriate concentration of SeMNPV has the potential to improve the efficacy of biological control against S. exigua.

Botanical Volatiles Selection in Mediating Electrophysiological Responses and Reproductive Behaviors for the Fall Webworm Moth Hyphantria cunea.

Host-plant volatiles play vital roles for insects to locate foraging, mating, and oviposition sites in the environment. As one of the devastating invasive forestry pests, Hyphantria cunea causes a great annual loss in China, and understanding its chemical ecology is an important task. The current research was done in terms of chemical analysis, electrophysiology, and behavioral assays on H. cunea to assess its olfactory reception toward host-plant volatiles. A screen of possible common host volatiles was done, targeting on five favored hosts of H. cunea, harvesting six potential bioactive compounds from a total of 78 odorant components. Six types of antennal sensilla were investigated on their distributions on the antennae, and sexual dimorphism was described. H. cunea showed responses to all selected host-related volatiles in electroantennogram tests, and linalyl butyrate elicited the strongest responses. Furthermore, mating rates in adult pairs that are exposed to dibutyl phthalate and phytol have been significantly increased, while oviposition rates and female fecundity were not influenced. The results of the current study provide initial evidence showing that universal host-derived volatile cues are essential for H. cunea moth in terms of mating, which can also provide insights into the development of botanical attractants.

[Study on the mechanism of energy transfer between fluorescein sodium and tetrabromofluorescein sodium in micelles of cationic surface active agent].

In the present paper, the fluorescence reaction of cationic surface-active agents (CSAA) with Tetrabromofluorescein sodium (TBF) in aqueous solution was investigated. It was found that the fluorescence quenching of TBF appears when it reacts with the cation monomer of a CSAA and a new stronger fluorescence is obtained when the ion-associates react with the micellate of CSAA. The authors investigated the condition of energy transfer between acidic fluorescent dyes in micelles of cetyl trimethyl ammonium bromide or hexadecyl pyridinium bromide. It was indicated that in the micelles formed by cationic surface active agent with dyes embedded (cationic surface active agent and dyes are charge opposite), the effective energy transfer between anionic dyes could occur. When the concentration of cationic surface active agent reached certain value, the energy transfer could occur. With the value of two thirds of critical micelle concentration, the efficiency of energy transfer reached the maximum; when the concentration of cationic surface active agent increased, the efficiency of energy transfer would be decreased. The authors also deduced the model of energy transfer between dyes in micelles and laws of it.

[Study on mechanism of lanthanide sensitized fluorescence energy transfer between terbium(III)-ciprofloxacin and rhodamine B].

A complex composed of ciprofloxacin and terbium (Tb3+) in the solution of acetic acid-sodium acetate buffer (pH 6.2) was studied by fluorescence spectroscopy and ultra-violet absorption spectroscopy. The emission peak of Tb3+ appeared at 490, 545, 590 nm, (the sensitized fluorescence was enforced mightily) and the intensity of 545 nm emission peak was increased obviously. In its acute emission spectrum, the strongest emission peak of Tb3+ was at 545 nm, which was close to the wavelength of the biggest absorption peak of RB, 552 nm. Therefore, as the basic dye rhodamine B(RB) was added, the fluorescence intensity of 545 nm emission peak decreased regularly, indicating that there was a great quenching process. The result showed that the course was statistic. Based on the mechanism of the Förster energy transfer, the efficiency of energy transfer and the distance between the acceptor RB and the complex were found. Thereby, it was indicated that the course of action was single static quenching and the mechanism of quenching was based on energy transfer.

Effects of altrenogest on reproductive performance of gilts and sows: A meta-analysis.

Altrenogest is a synthetic progestogen that allows for synchronization of the time of estrus in swine. Its effect on reproductive performance, however, is inconsistent due to conflicting data in the scientific literature. A meta-analysis of published data, therefore, was performed to determine whether altrenogest affects gilt and sow reproductive performance. Altrenogest administration to pigs enhanced the number of piglets born alive per litter (NBA), total number born per litter (TNB), estrous rate within 10 days after treatment (ER10) and pregnancy rate (PR) as well as the farrowing rate (FR) of gilts. The NBA and TNB of primiparous sows fed altrenogest were improved although FR was less. In multiparous sows, altrenogest treatment did not result in any improvement for any of the five analyzed variables. Additionally, 14-day treatment regimens for gilts and >8-days for primiparous sows improved reproductive performance and extent of estrous synchrony. The effects of altrenogest on reproductive performance of swine were parity and treatment duration dependent.

Enhancement of the biological activity of nucleopolyhedrovirus through disruption of the peritrophic matrix of insect larvae by chlorfluazuron.

The enhancement of Spodoptera litura (F.) nucleopolyhedrovirus (SlNPV) activity using the chitin synthesis inhibitor chlorfluazuron was investigated. When tested against fifth-instar S. litura larvae, chlorfluazuron produced synergistic effects at doses of 0.05 and 0.025 microg per insect, and additive effects at doses of 0.1 and 0.2 microg. Furthermore, the time required for SlNPV to kill larvae was significantly reduced by chlorfluazuron at all doses tested. The activity and killing speed of Autographa californica (Spey) nucleopolyhedrovirus (AcMNPV) against third-instar Spodoptera exigua (Hübner) larvae were similarly improved by chlorfluazuron at a dose of 0.05 microg per larva. Furthermore, the growth of S. exigua was significantly retarded by chlorfluazuron. Environmental scanning electron microscopy (ESEM) showed that the peritrophic matrices (PMs) of S. litura exposed to chlorfluazuron alone, or the combination treatment, were markedly disrupted. Obvious ruptures on the outer surfaces of the PM were observed, which potentially facilitated the passage of virions through the matrix.

[Study on the mechanism of energy transfer between acridine orange and rhodamine 6G in micelles of dodecyl benzene sodium sulfonate].

Applying Förster theory, the energy transfer between acridine orange (AO) and rhodamine 6G (R6G) was investigtaed. It was found that in the solution of dodecyl benzene sulfonic acid sodium (DBS), effective energy transfer can occur between AC and rhodamine 6G even when the concentration of the dyes is very low. The mechanism of energy transfer between AO and rhodamine 6G was studied. When the energy transfer occurs, the fluorescence of AO is quenched, the type of quenching is static. Based on the mechanism of Förster energy transference, the thermodynamic parameters, enthalpy change (deltaH) and entropy change (deltaS), were calculated according to Van't Hoff equation, which indicates the acting force between AO and R6G. The transfer efficiency of energy and the distance between AO and R6G were found. It is indicated that the course of action is single static quenching.

[Fluorescence resonance energy transfer quenching method for determination of arsenic with acridine orange-rhodamine B].

A new method for the determination of trace arsenic was developed by using fluorescence resonance energy transfer from acridine orange (AO) to rhodamine B (RB). It was found that under the condition of lambda(ex)/lambda(em) = 470/580 nm, effective energy transfer could occur between AO and RB in the dodecyl benzene sodium sulfonate solution. The fluorescence intensity of RB was diminished by molybdoarsenide which was formed by the reaction of arsenic (V) with molybdate in sulfuric acid medium. The detection limit of this method was 2. 56 microg x L(-1). This method was used for the determination of trace arsenic in tea. The range of determination for arsenic was 0.01-0.25 mg x L(-1). The relative standard deviation for the determination of arsenic was 0.48%-0.64%. The recoveries for the addition of 0.01-0.03 mg x L(-1) arsenic were 98%-103%. The method has been applied to the determination of arsenic with satisfactory results.

[Determination of vitamin B12 concentration by fluorescence quenching with acridine orange-rhodamine 6G energy transfer system].

An energy transfer technique between acridine orange (AO) and rhodamine 6G (R6G) was studied, and the optimum experimental conditions of energy transfer were defined. It was found that the effective energy transfer could occur between AO and R6G in the dodecylbenzene sodium sulfonate solution with Na2 HPO4-citric acid buffer solution at pH 5.0. The fluorescence intensity of AO-R6G system was diminished by vitamin B12 in an alkalescence medium. Based on the AO-R6G energy transfer system anovel fluorescence quenching method for the determination of vitamin B12 has been developed. Under optimal conditious, the linear range of calibration curves for the determination of vitamin B12 was 0-3.0 x 10(-5) mol x L(-1). The detection limits were 4.8 x 10(-7) mol x L(-1) for Vitamin B12. Among six times of determination, the relative standard deviation was 0.51%-0.64%, and the recovery was 98.40% -103.62%. The method features good recurrence, rapidity of reaction, good stability, and few interfering substances. It can be satisfactorily used in the determination of the injection content of vitamin B12.

[Spectrophotometric determination of albumin with acid brown SR].

A new method for the determination of albumin in human serum and mouse serum has been developed by spectrophotometry coupled with acid brown SR(ASR) as probe molecule. The maximum absorption wavelength of ASR was at 445 nm, while the maximum absorption wavelength of their product was at 610 nm. However, the reaction of ASR with albumin such as BSA or HSA was so strong that parts of their product were undissoluble in water. The addition of gum water into the system effectively eliminated the deposition. Under optimum reaction conditions, the ranges of working lines for BSA and HSA were 0-91.0 mg x L(-1) and 0-95.2 mg x L(-1), respectively. The detection limits were 5.72 mg x L(-1) for BSA and 5.15 mg x L(-1) for HSA. The relative standard derivation and the recovery of the method for the determination of total proteins in 6 human serum samples were 1.8%-4.4% and 93.6% - 109.1%, respectively. The proposed method has been employed in the assay of protein of human serum and mouse serum. The results of this work were in agreement with those obtained by Biuret method.

[Research on genetic variation of heart fatty acid-binding protein gene in ten pig breeds].

The genetic variation of heart fatty acid-binding protein (H-FABP) gene in 561 pigs including Duroc, Landrace, Large Yorkshire, Nanchang white pig, Erhualian, Meishan, Yushan black pig, Leping spotted pig, Jinhua black head-hind pig and Shanggao black head-hind pig were detected by PCR-RFLP with Hinf I, Hae III and Msp I. The results showed as follows: (1) Nanchang white pig presented only HH genotype while other breeds varied at the Hinf I-RFLP site; (2) The exotic breeds including Duroc, Landrace, Large Yorkshire and the native breed Nanchang white pig were proved to be polymorphic while the five Chinese local breeds presented no variation at the Hae III-RFLP site; (3) Among the tested breeds only Duroc presented variation at the Msp I-RFLP site. It is noted that all the Chinese local breeds present as AADD--genotypes.