Effects of an anal fistula plug on anal function after surgery for treatment of a trans-sphincteric anal fistula.

PURPOSE: The aim of this study was to evaluate the anal function in patients with trans-sphincteric anal fistulas who underwent an anal fistula plug procedure, and analyze risk factors that might affect post-operative anal function. METHODS: This was an observational, retrospective study of patients diagnosed with trans-sphincteric anal fistulas and initially underwent anal fistula plug procedures between August 2008 and September 2012 at our institute. The analysis includes clinical characteristics, anal fistula healing, and the Wexner score for pre- and post-operative anal function (0 = no incontinence to 20 = complete incontinence). RESULTS: A total of 123 patients who had an adequate follow-up in the end were included. The median duration of follow-up was 8 years (range 72-121 months). The overall healing rate was 56% (69/123), and 33 (26.8%) patients had decreased anal function after surgery. The post-operative Wexner score on anal function was significantly higher than that before the operation (p < 0.001), as well as scores of gas, liquid stool, solid stool incontinence, and alteration in lifestyle (p < 0.05). Based on multiple logistic regression analysis, a high body mass index (p < 0.001) and long distance between the external opening and anal verge (p = 0.003) were significantly associated with a decline in post-operative anal function. CONCLUSIONS: As a sphincter-preserving technique for the treatment of anal fistulas, the anal fistula plug procedure might impair the anal function. Especially for patients with obesity or long distance between the external opening of anal fistula and anal verge, the reduced anal function is more likely to occur after treatment with anal fistula plug therapy.

Long-Term Clinical Results of Use of an Anal Fistula Plug for Treatment of Low Trans-Sphincteric Anal Fistulas.

BACKGROUND An anal fistula plug is a sphincter-sparing procedure that uses biological substances to close an anorectal fistula. This study aimed to evaluate the long-term therapeutic effect of an anal fistula plug procedure in patients with trans-sphincteric fistula-in-ano and to determine the risk factors affecting fistula healing. MATERIAL AND METHODS A single-center retrospective study was performed assessing long-term treatment outcomes of patients with low trans-sphincteric anal fistulas who initially underwent anal fistula plug procedures between August 2008 and September 2012. Risk factors affecting fistula healing were identified using univariate and multivariate analyses. RESULTS A total of 135 patients who had low trans-sphincteric anal fistulas and underwent anal fistula plug procedures were analysed. The overall healing rate was 56% (75/135) with a median follow-up time of 8 years (range, 72-121 months). The primary reasons for treatment failure were plug extrusion (n=12, 20%) and surgical site infection (n=9, 15%), occurring within 30 days after surgery. Multiple logistic regression analysis showed that the duration of anal fistula ≥6 months was significantly associated with treatment failure using an anal fistula plug (OR=3.187, 95% CI: 1.361-7.466, P=0.008). Of the patients who failed initial treatment with an anal fistula plug, 6 (9%) had anal fistulas that healed spontaneously after 2-3 years without additional treatment. CONCLUSIONS As a sphincter-preserving procedure, the anal fistula plug can effectively promote healing of low trans-sphincteric anal fistulas. The long-term efficacy is good and the procedure warrants wider use in clinical practice.

Ligation of Intersphincteric Fistula Tract vs Ligation of the Intersphincteric Fistula Tract Plus a Bioprosthetic Anal Fistula Plug Procedure in Patients With Transsphincteric Anal Fistula: Early Results of a Multicenter Prospective Randomized Trial.

OBJECTIVE: The purpose of this study was to compare the ligation of intersphincteric fistula tract (LIFT) with an additional plug (LIFT-plug) in the treatment of transsphincteric anal fistula. SUMMARY BACKGROUND DATA: Both LIFT and LIFT-plug are recently reported effective alternatives of transsphincteric anal fistula. METHODS: This multicenter prospective randomized study (NCT01478139) was conducted at 5 university hospitals throughout China. A total of 235 patients were randomly assigned to undergo LIFT (118 patients) or LIFT-plug (117 patients) between March 2011 and April 2013. The primary outcome measured was primary healing rate at 6 months postoperatively and healing time. Secondary outcomes included recurrence rate, postoperative pain, and incontinence rate. RESULTS: The LIFT procedure showed shorter operative time than the LIFT-plug procedure (26.7 min vs 28.5 min, P = 0.03). Median healing time was 22 days in LIFT-plug group vs 30 days in LIFT group (P < 0.001). The difference in visual analog scale scores across all time points was not statistically significant between the groups (P = 0.13). The primary healing rate was higher in LIFT-plug group than in LIFT group [94.0% (95% confidence interval 89.7%-98.3%) vs 83.9% (95% confidence interval 77.2%-90.6%), P < 0.001]. There were no reported incontinence and recurrence within the follow-up period of 6 months. CONCLUSIONS: In patients with transsphincteric anal fistulas, both LIFT-plug and LIFT are simple, safe, and effective procedures. LIFT-plug has the advantage of a higher healing rate, less healing time, and a lower early postoperative pain score.

Expression Analysis and Binding Assays in the Chemosensory Protein Gene Family Indicate Multiple Roles in Helicoverpa armigera.

Chemosensory proteins (CSPs) have been proposed to capture and transport hydrophobic chemicals to receptors on sensory neurons. We identified and cloned 24 CSP genes to better understand the physiological function of CSPs in Helicoverpa armigera. Quantitative real-time polymerase chain reaction assays indicate that CSP genes are ubiquitously expressed in adult H. armigera tissues. Broad expression patterns in adult tissues suggest that CSPs are involved in a diverse range of cellular processes, including chemosensation as well as other functions not related to chemosensation. The H. armigera CSPs that were highly transcribed in sensory organs or pheromone glands (HarmCSPs 6, 9, 18, 19), were recombinantly expressed in bacteria to explore their function. Fluorescent competitive binding assays were used to measure the binding affinities of these CSPs against 85 plant volatiles and 4 pheromone components. HarmCSP6 displays high binding affinity for pheromone components, whereas the other three proteins do not show affinities for any of the compounds tested. HarmCSP6 is expressed in numerous cells located in or close to long sensilla trichodea on the antennae of both males and females. These results suggest that HarmCSP6 may be involved in transporting female sex pheromones in H. armigera.

Odorant-binding proteins display high affinities for behavioral attractants and repellents in the natural predator Chrysopa pallens.

Chrysopa pallens is an important natural predator of various pests in many different cropping systems. Understanding the sophisticated olfactory system of insect antennae is crucial for studying the physiological bases of olfaction and could also help enhance the effectiveness of C. pallens in biological control. However, functional studies of the olfactory genes in C. pallens are still lacking. In this study, we cloned five odorant-binding protein (OBP) genes from C. pallens (CpalOBPs). Quantitative RT-PCR results indicated that the five CpalOBPs had different tissue expression profiles. Ligand-binding assays showed that farnesol, farnesene, cis-3-hexenyl hexanoate, geranylacetone, beta-ionone, octyl aldehyde, decanal, nerolidol (Ki<20 µM), and especially 2-pentadecanone (Ki=1.19 µM) and 2-hexyl-1-decanol (Ki=0.37 µM) strongly bound to CpalOBP2. CpalOBP15 exhibited high binding affinities for beta-ionone, 2-tridecanone, trans-nerolidol, and dodecyl aldehyde. Behavioral trials using the 14 compounds exhibiting high binding affinities for the CpalOBPs revealed that nine were able to elicit significant behavioral responses from C. pallens. Among them, farnesene and its corresponding alcohol, farnesol, elicited remarkable repellent behavioral responses from C. pallens. Our study provides several compounds that could be selected to develop slow-release agents that attract/repel C. pallens and to improve the search for strategies to eliminate insect pests.

[The effects of transgenic Cry1Ac+Cry2Ab cotton on cotton bollworm control and functional response of predators on whitefly].

In this study, we detected and clarified the roles of transgenic Cry1Ac+Cry2Ab cotton "639020" in controlling cotton bollworm (Helicoverpa armigera) during critical periods of bud stage (second generation of bollworm), flowering stage (third generation of bollworm) and bolling stage (fourth generation of bollworm) as well as the influences of 639020 cotton on functional response of the main predators (Chrysopa sinica larvae, Propylaea japonica, Orius and Erigonidium graminicola ) on whitefly using transgenic Cry1Ac cotton "CCRI41" and conventional cotton "CCRI49" as the control. Our results showed that the 639020 cotton well controlled the second and third generation of bollworm, and the level of insect resistance increased by 52.85% and 16.22% separately compared with that of CCRI41, with a significant effect on the second generation of bollworm. Moreover, the number of bollworm eggs in 639020 cotton field was lower than that in CCRI41 and CCRI49 cotton fields (except the second generation of bollworm) during the cotton bud, flowering and bolling stages. Although the number of bollworm larvae in 639020 cotton field was significantly lower than that in CCRI49 field, and both under the controlling index, it has no significant difference compared with that in CCRI41 cotton field. There were also no obvious changes in predator functions of Chrysopa sinica, Propylaea japonica, Orius and Erigonidium graminicola on bemisia tabaci between 639020, CCRI41 and CCRI49 cotton filed. This study evaluated the safety of new transgenic cotton on environment, anti-insect activity of exogenous gene and the safety of production and application prospect.

A cadherin-like protein from the beet armyworm Spodoptera exigua (Lepidoptera: Noctuidae) is a putative Cry1Ac receptor.

In S. exigua, ingestion of Cry1Ac reduces larval growth, shortens lifespan, and decreases copulation and oviposition of the adults. Cadherin-like protein SeCad1b in S. exigua has recently been published. Here, we tested whether SeCad1b mediates the negative effects of Cry1Ac. We identified three potential Cry toxin binding regions in SeCad1b, i.e., (879) EIAIQITDTNN(889) , (1357) SLLTVTI(1363) , and (1436) GVISLNFQ(1443) . We expressed and purified a truncated cadherin, rSeCad1bp, and its interspecific homologue, rHaBtRp, from H. armigera that contain the putative toxin binding regions. Using a toxin overlay assay, we found that rSeCad1bp specifically binds to biotinylated Cry1Ac in a dose-dependent manner. We also discovered that an addition of rSeCad1bp and rHaBtRp enhances the suppression of larval growth by Cry1Ac, although rSeCad1bp is less suppressive than rHaBtRp. Finally, RNA interference-mediated knockdown of SeCad1b reduced approximately 80% of the target gene and significantly alleviated the negative effect of CrylAc on larval growth. We infer that the S. exigua SeCad1b is a functional receptor of Cry1Ac.

A Spodoptera exigua cadherin serves as a putative receptor for Bacillus thuringiensis Cry1Ca toxin and shows differential enhancement of Cry1Ca and Cry1Ac toxicity.

Crystal toxin Cry1Ca from Bacillus thuringiensis has an insecticidal spectrum encompassing lepidopteran insects that are tolerant to current commercially used B. thuringiensis crops (Bt crops) expressing Cry1A toxins and may be useful as a potential bioinsecticide. The mode of action of Cry1A is fairly well understood. However, whether Cry1Ca interacts with the same receptor proteins as Cry1A remains unproven. In the present paper, we first cloned a cadherin-like gene, SeCad1b, from Spodoptera exigua (relatively susceptible to Cry1Ca). SeCad1b was highly expressed in the larval gut but scarcely detected in fat body, Malpighian tubules, and remaining carcass. Second, we bacterially expressed truncated cadherin rSeCad1bp and its interspecific homologue rHaBtRp from Helicoverpa armigera (more sensitive to Cry1Ac) containing the putative toxin-binding regions. Competitive binding assays showed that both Cry1Ca and Cry1Ac could bind to rSeCad1bp and rHaBtRp, and they did not compete with each other. Third, Cry1Ca ingestion killed larvae and decreased the weight of surviving larvae. Dietary introduction of SeCad1b double-stranded RNA (dsRNA) reduced approximately 80% of the target mRNA and partially alleviated the negative effect of Cry1Ca on larval survival and growth. Lastly, rSeCad1bp and rHaBtRp differentially enhanced the negative effects of Cry1Ca and Cry1Ac on the larval mortalities and growth of S. exigua and H. armigera. Thus, we provide the first lines of evidence to suggest that SeCad1b from S. exigua is a functional receptor of Cry1Ca.

Identification and binding characterization of three odorant binding proteins and one chemosensory protein from Apolygus lucorum (Meyer-Dur).

For the sucking insect, Apolygus lucorum, taste is essential for finding host plants and oviposition sites. In A. lucorum, taste relies largely on the sensory system located within its proboscis. In this study, we constructed a cDNA library from A. lucorum proboscises and conducted preliminary analysis of 1554 ESTs. From this collection, we identified three putative odorant-binding proteins (AlucOBP3, AlucOBP4, AlucOBP6) and one chemosensory protein (AlucCSP1). Quantitative real-time polymerase chain reaction (qPCR) was used to study the expression pattern of these four genes. All four were expressed mainly in antennae, proboscises and legs, suggestive of roles in olfaction and gustation. We expressed and purified recombinant versions of AlucOBP3, AlucOBP4, AlucOBP6, and AlucCSP1 in a prokaryotic expression system. The ligand-binding specificities of the four proteins then were investigated in competition assays using 4,4'-dianilino-1,1'-binaphthyl-5, 5'-sulfonic acid (bis-ANS) as a probe. Of the 58 small organic compounds and five cotton secondary metabolites tested, plant volatiles cannot effectively displace bis-ANS from any of the four proteins. In contrast, most of the cotton secondary metabolites have high affinities for the three OBPs and AlucCSP1, indicating that these binding proteins more likely play a role in gustation than in olfaction.

Binding characterization of recombinant odorant-binding proteins from the parasitic wasp, Microplitis mediator (Hymenoptera: Braconidae).

Chemoreception in insects is mediated by small odorant-binding proteins (OBPs) that are believed to carry lipophilic stimuli to the olfactory receptor cells through the aqueous sensillar lymph. Binding experiments and recent structural studies of OBPs have illustrated their versatility and ability to accommodate ligands of different shapes and chemical structures. We expressed and purified seven recombinant OBPs (MmedOBP1-MmedOBP7) from the parasitic wasp, Microplitis mediator (Hymenoptera: Braconidae) in a prokaryotic expression system. With 4,4'-dianilino-1,1'-binaphthyl-5,5'-sulfonic acid (bis-ANS) as a fluorescent probe, the ligand-binding specificities of these seven MmedOBPs with 50 small organic compounds were investigated in vitro. The results revealed that all of the M. mediator OBPs can bind a wide variety of odorant molecules with different binding affinities. The best ligand for all seven MmedOBPs was ß-ionone. MmedOBP2 showed affinity for some aromatic compounds, whereas MmedOBP4 and MmedOBP6 bound several terpenoids. MmedOBP5 bound ß-ionone, but did not bind any of the other potential ligands that we tested.

Sublethal Exposure to Deltamethrin Stimulates Reproduction and Alters Symbiotic Bacteria in Aphis gossypii.

In aphids, hormesis and symbiotic bacteria are the drivers for the development of pesticide resistance. However, the related mechanism remains unclear. Here, we evaluated the sublethal and transgenerational effects of the extensively used pyrethroid pesticide deltamethrin (DMT) on the population dynamics in Aphis gossypii and tested its influence on symbiotic bacterial communities. The leaf-dip bioassay revealed that DMT was highly toxic to A. gossypii, and at a low lethal concentration of DMT, the intrinsic (r) and finite rates of increase (λ) of the initially exposed aphids (G0) significantly decreased. Intriguingly, the r, λ, and net reproductive rate (R0) of G1 and G2 significantly increased, but the r and λ decreased in G3. The adult and total preoviposition period increased in G3 but decreased in G4. Additionally, the diversity of the bacterial community decreased, while the abundance values of Buchnera, Pseudomonadaceae, and Burkholderiaceae increased after 24 h of exposure to LC30 DMT in G0 aphids, and the latter two decreased in G1 but increased in G2. In summary, sublethal DMT has intergenerational hormesis effect on cotton aphids in G1-G2 and remarkably altered their symbiotic bacterial community and abundance. These results broaden our understanding of the relationship of hormesis and symbiotic bacteria in aphids under insecticide exposure.

Evaluation of sublethal and transgenerational effects of sulfoxaflor on Aphis gossypii via life table parameters and 16S rRNA sequencing.

BACKGROUND: Aphis gossypii, a polyphagous and recurrent pest induced by pesticides, causes tremendous loss crop yields each year. Previous studies on the mechanism of pesticide-induced sublethal effects mainly focus on the gene level. The symbiotic bacteria are also important participants of this mechanism, but their roles in hormesis are still unclear. RESULTS: In this study, life table parameters and 16S rRNA sequencing were applied to evaluate the sublethal and transgenerational effects of sulfoxaflor on adult A. gossypii after 24-h LC20 (6.96 mg L-1 ) concentration exposure. The results indicated that the LC20 of sulfoxaflor significantly reduced the finite rate of increase (λ) and net reproductive rate (R0 ) of parent generation (G0), and significantly increased mean generation time (T) of G1 and G2, but not of G3 and G4. Both reproductive period and fecundity of G1 and G2 were significantly higher than those of the control. Furthermore, our sequencing data revealed that more than 95% bacterial communities were dominated by the phylum Proteobacteria, in which the maximum proportion genus was the primary symbiont Buchnera and the facultative symbiont Arsenophonus. Compared to those of the control, the abundance and composition of symbiotic bacteria of A. gossypii for three successive generations (G0-G2) were changed after G0 A. gossypii was exposed to sulfoxaflor: the diversity of the bacterial community was decreased, but the abundance of Buchnera was increased (G0), while the abundance of Arsenophonus was decreased. Contrary to G0, G1 and G2 cotton aphid exhibited an increased relative abundance of Arsenophonus in the sublethal treatment group. CONCLUSION: Taken together, our results provide an insight into the interactions among pesticide resistance, aphids, and symbionts, which will eventually help to better manage the resurgence of A. gossypii. © 2021 Society of Chemical Industry.

Use of an innovative T-tube maze assay and the proboscis extension response assay to assess sublethal effects of GM products and pesticides on learning capacity of the honey bee Apis mellifera L.

Transgenic Cry1Ac+CpTI cotton (CCRI41) is a promising cotton cultivar throughout China but side effects and especially sublethal effects of this transgenic cultivar on beneficial insects remain poorly studied. More specifically potential sublethal effects on behavioural traits of the honey bee Apis mellifera L. have not been formally assessed despite the importance of honey bees for pollination. The goal of our study was to assess potential effects of CCRI41 cotton pollen on visual and olfactory learning by honey bees. After a 7-day oral chronic exposure to honey mixed with either CCRI41 pollen, imidacloprid-treated conventional pollen (used as positive sublethal control) or conventional pollen (control), learning performance was evaluated by the classical proboscis extension reflex (PER) procedure as well as a T-tube maze test. The latter assay was designed as a new device to assess potential side effects of pesticides on visual associative learning of honey bees. These two procedures were complementary because the former focused on olfactory learning while the latter was involved in visual learning based on visual orientation ability. Oral exposure to CCRI41 pollen did not affect learning capacities of honey bees in both the T-tube maze and PER tests. However, exposure to imidacloprid resulted in reduced visual learning capacities in T-tube maze evaluation and decreased olfactory learning performances measured with PER. The implications of these results are discussed in terms of risks of transgenic CCRI41 cotton crops for honey bees.

Quantification of toxins in a Cry1Ac + CpTI cotton cultivar and its potential effects on the honey bee Apis mellifera L.

Transgenic Cry1Ac + CpTI cotton (CCRI41) is increasingly planted throughout China. However, negative effects of this cultivar on the honey bee Apis mellifera L., the most important pollinator for cultivated ecosystem, remained poorly investigated. The objective of our study was to evaluate the potential side effects of transgenic Cry1Ac + CpTI pollen from cotton on young adult honey bees A. mellifera L. Two points emphasized the significance of our study: (1) A higher expression level of insecticidal protein Cry1Ac in pollen tissues was detected (when compared with previous reports). In particular, Cry1Ac protein was detected at 300 ± 4.52 ng g(-1) [part per billion (ppb)] in pollen collected in July, (2) Effects on chronic mortality and feeding behaviour in honey bees were evaluated using a no-choice dietary feeding protocol with treated pollen, which guarantee the highest exposure level to bees potentially occurring in natural conditions (worst case scenario). Tests were also conducted using imidacloprid-treated pollen at a concentration of 48 ppb as positive control for sublethal effect on feeding behaviour. Our results suggested that Cry1Ac + CpTI pollen carried no lethal risk for honey bees. However, during a 7-day oral exposure to the various treatments (transgenic, imidacloprid-treated and control), honey bee feeding behaviour was disturbed and bees consumed significantly less CCRI41 cotton pollen than in the control group in which bees were exposed to conventional cotton pollen. It may indicate an antifeedant effect of CCRI41 pollen on honey bees and thus bees may be at risk because of large areas are planted with transgenic Bt cotton in China. This is the first report suggesting a potential sublethal effect of CCRI41 cotton pollen on honey bees. The implications of the results are discussed in terms of risk assessment for bees as well as for directions of future work involving risk assessment of CCRI41 cotton.

The effect of root exudates from two transgenic insect-resistant cotton lines on the growth of Fusarium oxysporum.

The attenuation of disease resistance in transgenic insect-resistant cotton has become one of the important factors restricting cotton production in China. Two transgenic insect-resistant cotton lines and their parental conventional cotton lines were used as the testing materials. The effects of root exudates of these cotton lines on the spore germination and mycelial growth of Fusarium oxysporum were studied and the components, contents of amino acids and sugars were determined. The results showed that the resistance of the two insect-resistant cotton lines to F. oxysporum was inferior to the parental lines, and that their root exudates promoted fungal spore germination and mycelial growth. Considerable differences in the components and contents of both, amino acids and sugars were found between the root exudates of transgenic cotton lines and their parental lines, where the disease indices were highly correlated with the total amount of sugars in the root exudates.

[Effect of akebiasaponin D with different concentrations on orthodontic tooth movement in rats].

PURPOSE: This study investigated the effect of local injection of akebiasaponin D (ASD) with different concentrations on the rate of orthodontic tooth movement in rats. METHODS: Forty 6-week-old female Wistar rats were randomly divided into 4 groups with 10 rats in each group. Animal model for orthodontic tooth movement was established. The upper first molars of the rats were moved mesially by coil springs（force=40 g）. ASD solution at the concentration of 5 mg/kg was locally injected in ASD1 group, and ASD solution at the concentration of 10 mg/kg was locally injected in ASD2 group. The rats of group PGE2 were injected PGE2 solution at the concentration of 25 µg/kg. The same amount of normal saline was injected in the control group. The rats were sacrificed in batch on the 3rd, 7th, 14th, 21st and 28th days after orthodontic treatment. The distance between upper first molar and second molar was measured. H-E straining was performed to observe the changes of periodontal tissue and the amount of osteoclast. SPSS13.0 software package was used for statistical analysis. RESULTS: The distance between the first and second molar was successively increased compared with the control group. On day 3, there was significant difference between PGE2 group and the control group (P＜0.05). On day 7, the distance between the first and second molar in PGE2 group and ASD2 group was significantly increased compared with the control group (P＜0.05). The amount of tooth movement was significantly increased (P＜0.05) in ASD1 group, ASD2 group and PGE2 group, compared with the control group on the 14th, 21st and 28th day. However, there was no significant difference (P＞0.05) between ASD2 group and PGE2 group. Under microscope, the number of osteoclast was increased on the tension side, reaching a peak on day 21st, and decreased later. CONCLUSIONS: Local injection of ASD solution may accelerate orthodontic tooth movement. ASD solution at the dose of 10 mg/kg can accelerate orthodontic tooth movement efficiently similar to PGE2 solution, while ASD solution at the dose of 5 mg/kg is not as effectual as PGE2 solution.

Effect of NaCl-stressed Bacillus thuringiensis (Bt) cotton on the feeding behaviors and nutritional parameters of Helicoverpa armigera.

Saline-alkali soil is an arable land resource on which transgenic Bacillus thuringiensis (Bt) cotton has been planted on a large scale in accordance with food security strategies. There are, however, concerns about the insecticidal effects of Bt cotton on target insect pests. In this study, a Bt cotton variety, GK19, and its nontransgenic parent variety, Simian-3, were used as experimental models for investigating the effect of the expression of exogenous insecticidal proteins in Bt cotton under NaCl stress on the feeding behavior and nutritional parameters of Helicoverpa armigera. The results showed that the expression of exogenous insecticidal proteins in GK19 was significantly inhibited under NaCl stress. However, the feeding, crawling, resting and spinning down behavior of the 5th instar H. armigera larvae on GK19 Bt cotton, as well as the amount of food consumed and feces produced by these larvae, did not markedly differ under different NaCl concentrations. In contrast, the mean relative growth rate (MRGR), relative growth rate (RGR), approximate digestibility (AD), efficiency of conversion of ingested food (ECI) and efficiency of conversion of digested food (ECD) of the larvae markedly decreased in response to NaCl stress. Under the same concentration of NaCl, the nutritional parameters of the bollworm larvae on GK19 Bt cotton or Simian-3 nontransgenic cotton were different. However, the interaction between salt stress and cotton variety had no significant effect on the feeding behavior or nutritional parameters of H. armigera larvae. These results may provide a scientific basis for determining the effect of exogenous insecticidal protein expression in Bt cotton under NaCl stress on H. armigera and can therefore be useful for the effective application of Bt cotton in saline-alkali soils to prevent and control H. armigera.

Distinct binding affinities of odorant-binding proteins from the natural predator Chrysoperla sinica suggest different strategies to hunt prey.

Chrysoperla sinica is an important natural predator of many notorious agricultural pests. Understanding its olfactory mechanism can help enhance the effectiveness of C. sinica in biological control. In the present study, we investigated the tissue expression patterns of 12 odorant-binding protein (OBP) genes from C. sinica (CsinOBPs). The results of quantitative real-time polymerase chain reaction (qPCR) showed that CsinOBP1, CsinOBP2, CsinOBP3, CsinOBP4, CsinOBP6, CsinOBP7, CsinOBP9, CsinOBP10, and CsinOBP12 were predominantly expressed in the antennae of both sexes, indicating their roles in olfaction. Additionally, the qPCR analysis revealed that the 12 CsinOBP genes had distinct expression patterns, while the motif-pattern investigation suggested that the OBPs had different ligands. The ligand-binding assay showed that CsinOBP1 and CsinOBP10 had broader binding spectra than did the other OBPs. Thus, CsinOBP1 was able to bind not only plant volatiles (such as farnesol, cis-3-hexenyl hexanoate, geranylacetone, ß-ionone, 2-tridecanone, and trans-nerolidol) but also the aphid alarm pheromone (E)-ß-farnesene. On the other hand, CsinOBP2 and CsinOBP6 exhibited relatively narrow binding spectra, only binding ethyl benzoate. The study also identified several compounds that can potentially be used to develop slow-release agents attracting C. sinica and to improve search strategies for insect pest control.

An example of host plant expansion of host-specialized Aphis gossypii Glover in the field.

The host plant expansion of host-specialized Aphis gossypii (Glover) has been well studied in the laboratory; however, this phenomenon is poorly understood in the field. Here, we provide a series of laboratory and field experiments to assess the role of zucchini in the host plant expansion of cotton-specialized aphids. We observed that cotton-specialized aphids possessed the ability to expand on a new host plant (cucumber), with individuals first recorded on June 12 and consequently increasing exponentially in number in a field cage. A bioassay experiment showed that aphids from both cotton and cucumber preferred their natal host, but clones from zucchini have a stronger preference for cucumber than cotton or zucchini. A total of 1512 individuals were collected from a cotton field (mixed cotton and cucurbit plot), cotton farmland (cotton alone) and a field cage and sequenced to identify their biotypes. The results for apterous individuals from the cotton field showed that more cucurbit-specialized biotypes occurred on cucumber and more cotton-specialized biotypes occurred on cotton and zucchini. A majority (> 97.0%) of aphids from both the field cage and cotton farmland were cotton-specialized individuals. Consequently, eliminating intermediate host plants may be an effective measure to suppress A. gossypii outbreaks, because cotton and cucumber are often grown together in fields and greenhouses.

Phylogeographic patterns of Lygus pratensis (Hemiptera: Miridae): Evidence for weak genetic structure and recent expansion in northwest China.

Lygus pratensis (L.) is an important cotton pest in China, especially in the northwest region. Nymphs and adults cause serious quality and yield losses. However, the genetic structure and geographic distribution of L. pratensis is not well known. We analyzed genetic diversity, geographical structure, gene flow, and population dynamics of L. pratensis in northwest China using mitochondrial and nuclear sequence datasets to study phylogeographical patterns and demographic history. L. pratensis (n = 286) were collected at sites across an area spanning 2,180,000 km2, including the Xinjiang and Gansu-Ningxia regions. Populations in the two regions could be distinguished based on mitochondrial criteria but the overall genetic structure was weak. The nuclear dataset revealed a lack of diagnostic genetic structure across sample areas. Phylogenetic analysis indicated a lack of population level monophyly that may have been caused by incomplete lineage sorting. The Mantel test showed a significant correlation between genetic and geographic distances among the populations based on the mtDNA data. However the nuclear dataset did not show significant correlation. A high level of gene flow among populations was indicated by migration analysis; human activities may have also facilitated insect movement. The availability of irrigation water and ample cotton hosts makes the Xinjiang region well suited for L. pratensis reproduction. Bayesian skyline plot analysis, star-shaped network, and neutrality tests all indicated that L. pratensis has experienced recent population expansion. Climatic changes and extensive areas occupied by host plants have led to population expansion of L. pratensis. In conclusion, the present distribution and phylogeographic pattern of L. pratensis was influenced by climate, human activities, and availability of plant hosts.