Iron accumulation induced by hepcidin1 knockout accelerates the progression of aging osteoporosis.

OBJECTIVE: Iron accumulation is associated with osteoporosis. This study aims to explore the effect of chronic iron accumulation induced by hepcidin1 deficiency on aging osteoporosis. METHODS: Iron accumulation in hepcidin1 knockout aging mice was assessed by atomic absorption spectroscopy and Perl's staining. Bone microarchitecture was observed using Micro-CT. Hepcidin, ferritin, oxidative stress, and markers of bone turnover in serum were detected by enzyme-linked immunosorbent assay. Bone formation and resorption markers were measured by real-time quantitative PCR. Cell aging was induced by D-galactose treatment. CCK-8, flow cytometry, EdU assays, and Alizarin red staining were performed to reveal the role of hepcidin1 knockout in cell model. Iron Colorimetric Assay Kit and western blot were applied to detect iron and ferritin levels in cells, respectively. RESULTS: In hepcidin1-knockout mice, the ferritin and iron contents in liver and tibia were significantly increased. Iron accumulation induced by hepcidin1 knockout caused a phenotype of low bone mass and deteriorated bone microarchitecture. Osteogenic marker was decreased and osteoclast marker was increased in mice, accompanied by increased oxidative stress level. The mRNA expression levels of osteoclast differentiation markers (RANKL, Mmp9, OPG, Trap, and CTSK) were up-regulated, while bone formation markers (OCN, ALP, Runx2, SP7, and Col-1) were down-regulated in model group, compared to wild type mice. In vitro, hepcidin1 knockdown inhibited proliferation and osteogenic differentiation, while promoted apoptosis, with increased levels of iron and ferritin. CONCLUSION: Iron accumulation induced by hepcidin1 deficiency aggravates the progression of aging osteoporosis via inhibiting osteogenesis and promoting osteoclast genesis.

Life Table Construction under Different Temperatures and Insecticide Susceptibility Analysis of Uroleucon formosanum (Hemiptera: Aphididae).

Uroleucon formosanum is an important aphid pest of lettuce, but basic information on its biology is scarce. In this study, effects of three constant temperatures (17, 21, and 25 °C, simulating the mean temperature range in greenhouses) on the development and fecundity of U. formosanum were analyzed by constructing a life table. U. formosanum could develop and reproduce under all three temperatures, but the survival rate, development, and fecundity of U. formosanum were affected by temperature. The intrinsic rate of increase was lowest at 17 °C (0.17) and it was significantly less than at 21 °C (0.20) and 25 °C (0.23). Furthermore, U. formosanum had the lowest finite rate of increase (1.19) and the largest mean generation time (20.21) at 17 °C. These results mean that U. formosanum is less adapted to the lower temperatures (17 °C) among these three set temperatures. To screen insecticides for control, susceptibility of U. formosanum to six insecticides including chlorpyrifos, abamectin, beta-cypermethrin, imidacloprid, nitenpyram, and thiamethoxam was evaluated. U. formosanum was relatively sensitive to all six test insecticides. Chlorpyrifos had the highest toxicity to U. formosanum (LC50 = 3.08 mg/L). These data may help to develop integrated management strategies for better population control of U. formosanum.

Perception of and Behavioral Responses to Host Plant Volatiles for Three Adelphocoris Species.

In China, the genus Adelphocoris (Hemiptera: Miridae) includes three dominant pest species (A. suturalis, A. lineolatus and A. fasciaticollis), which cause great damage to cotton, alfalfa and other crops. In this study, we examined the role of the major volatile organic compounds from plants in host location by these three insects. Gas chromatography-electroantennography and gas chromatography/mass spectrometry analyses identified seven electroantennogram (EAG)-active compounds from 11 host plants. Although the insects responded to all of these compounds in EAG trials, some compounds did not elicit behavioral responses in Y-tube olfactometer bioassays. Adelphocoris suturalis adults showed behavioral responses to four EAG-active compounds, n-butyl ether, butyl acrylate, butyl propionate and butyl butyrate. These four compounds, in addition to p-xylene, were also attractive to A. lineolatus adults. However, A. fasciaticollis adults were attracted only by butyl acrylate, butyl propionate and butyl butyrate. In field trials, A. suturalis and A. fasciaticollis were each attracted to five individual compounds (m-xylene, n-butyl ether, butyl acrylate, butyl butyrate and butyl propionate for A. suturalis and m-xylene, butyl acrylate, butyl butyrate, butyl propionate, and 1,8-cineole for A. fasciaticollis). By contrast, A. lineolatus aduts were attracted to six individual compounds, m-xylene, p-xylene, n-butyl ether, butyl acrylate, butyl butyrate, and butyl propionate. These compounds may be important in host plant location by the Adelphocoris species, and may be useful for developing attractants for adults of these species.

The specific host plant DNA detection suggests a potential migration of Apolygus lucorum from cotton to mungbean fields.

The polyphagous mirid bug Apolygus lucorum (Heteroptera: Miridae) has more than 200 species of host plants and is an insect pest of important agricultural crops, including cotton (Gossypium hirsutum) and mungbean (Vigna radiata). Previous field trials have shown that A. lucorum adults prefer mungbean to cotton plants, indicating the considerable potential of mungbean as a trap crop in cotton fields. However, direct evidence supporting the migration of A. lucorum adults from cotton to mungbean is lacking. We developed a DNA-based polymerase chain reaction (PCR) approach to reveal the movement of A. lucorum between neighboring mungbean and cotton fields. Two pairs of PCR primers specific to cotton or mungbean were designed to target the trnL-trnF region of chloroplast DNA. Significant differences in the detectability half-life (DS50) were observed between these two host plants, and the mean for cotton (8.26 h) was approximately two times longer than that of mungbean (4.38 h), requiring weighted mean calculations to compare the detectability of plant DNA in the guts of field-collected bugs. In field trials, cotton DNA was detected in the guts of the adult A. lucorum individuals collected in mungbean plots, and the cotton DNA detection rate decreased successively from 5 to 15 m away from the mungbean-cotton midline. In addition to the specific detection of cotton- and mungbean-fed bugs, both cotton and mungbean DNA were simultaneously detected within the guts of single individuals caught from mungbean fields. This study successfully established a tool for molecular gut-content analyses and clearly demonstrated the movement of A. lucorum adults from cotton to neighboring mungbean fields, providing new insights into understanding the feeding characteristics and landscape-level ecology of A. lucorum under natural conditions.

[Effects of low-concentration Cry1Ac toxic protein on growth and reproduction of three successive generations of Sylepta derogata population]. / 低浓度Cry1Ac毒蛋白对棉大卷叶螟连续三代生长发育与繁殖的影响.

Cotton leaf roller Sylepta derogata causes serious damage to cotton at the later growing stages of cotton. A leaf-dip method was used to measure the effects of low-concentration CrylAc toxic protein on the development and population growth of three successive generations of cotton leaf rol-lers in this study. The larval duration of Bt-fed S. derogata was 1.78-2.00 d longer, adult life span 1.44-1.94 d longer, and pupal mass 5.3%-11.8% higher than those of the control, respectively. The egg counts per female in the three generations were 65.1%, 47.3% and 37.6% higher, respectively, than those of the control, and the indexes of population trend were 11.4%, 17.5% and 20.0% greater, respectively. No significant differences were found in the duration of pupa duration, the emergence rate, the sex ratio, or the hatch rate. It was suggested that the population of cotton leaf rollers would steadily increase during the later stage of transgenic Bt cotton growth, therefore, further risk assessments of transgenic cotton and comprehensive management of these pests in cotton fields were needed.

[Ecological Effects of Algae Blooms Cluster: The Impact on Chlorophyll and Photosynthesis of the Water Hyacinth].

The response of chlorophyll and photosynthesis of water hyacinth leaves in different concentrations of clustered algae cells was studied in the simulation experiment, and the aim was to reveal the mechanism of the death of aquatic plants during algae blooms occurred through studying the physiological changes of the macrophytes, so as to play the full function of the ecological restoration of the plants. And results showed the dissolved oxygen quickly consumed in root zone of aquatic plants after algae blooms gathered and showed the lack of oxygen (DO < 0.2 g x L(-1)); and the ORP was lower than -100 mV after 1 d, and it declined to -200 mV at the end of the experiment. There were lots of nutrients releasing to the water after the algae cell died and concentration of DTN in treatment 1 and 2 were 44.49 mg x L(-1) and 111.32 mg x L(-1), and the content of DTP were 2.57 mg x L(-1) and 9.10 mg x L(-1), respectively. The NH4+ -N concentrations were as high as 32.99 mg x L(-1) and 51.22 mg x L(-1), and the root zone with the anoxia, strong reducing, higher nutrients environment had a serious stress effects to the aquatic plants. The macrophytes photosynthesis reduced quickly and the plant body damaged with the intimidation of higher NH4+ -N concentration (average content was 45.6 mg x L(-1)) and hypoxia after algae cell decomposed. The average net photosynthesis rate, leaf transpiration rate of the treatment 2 reduced to 3.95 micromol (M2 x S)(-1), 0.088 micromol x (m2 x s)(-1), and only were 0.18 times, 0.11 times of the control group, respectively, at the end of the experiment, the control group were 22 micromol x (m2 x s)(-1), 0.78 micromol x (M2 x s)(-1). Results indicated the algae bloom together had the irreversible damage to the aquatic plants. Also it was found large amounts of new roots and the old roots were dead in the treatment 1, but roots were all died in the treatment 2, and leaves were yellow and withered. Experiment results manifested that the serious environment caused by the algae blooms together was the main reason of the death of aquatic plants during the summer. So in the practice of ecological restoration, it should avoid the harm to the plant after the algae bloom cells gathered and decomposed, so as to play the purification function of the plant in the ecological rehabilitation project.

[Accumulation of lead in Spodoptera exigua (Hübner) and its impact on the population].

The heavy metals pollution is one of the ecological problems which have been paid close attention to Spodoptera exigua Hübner, one of the key pests on vegetables and cotton in the Yangtze River and its southern area in China, has broken out more frequently in recent years. In this study, accumulation of Pb2+ in S. exigua and its excretion were detected when fed with artificial diets with different Pb2+ concentrations (0.3, 1.2, 4.8, 19.2 and 76.8 mg x kg(-1), respectively). Life table was constructed according to the survival and growth of different stages of S. exigua. The effect of lead on three successive generations of beet armyworm was studied using the life table in the laboratory. It was found that the Pb2+ contents were significantly different when S. exigua was reared at different Pb2+ concentrations in the same generation in a significant dose-dependent manner. The concentration of Pb2+ increased with prolonging the stress time at the same time. The Pb2+ concentrations at the three developmental stages of beet armyworm followed the order of larvae > adult > pupa. The beet armyworm could excrete heavy metals by means of faeces, prepupa exuviate and puparium, and the concentrations of Pb2+ in faeces and prepupa exuviate were far higher than in puparium. According to the survival rates of different developmental stages, the female ratios and the egg numbers, the laboratory population life table was constructed. It showed that low doses of Pb2+ promoted the growth of the population, and high doses inhibited the growth, and the index of population trend (I) declined more rapidly with the increase of stress time. The study could provide references for long-term and objective assessment of heavy metal hazard and its effect on the populations of important agricultural pests.

Accumulation and excretion of cadmium in three successive generations of Spodoptera exigua (Lepidoptera: Noctuidae) and impact on the population increase.

Nowadays, heavy metal pollution has become more and more serious. Cadmium is one of the heavy metals that have caused serious pollution. Spodoptera exigua Hübner (Lepidoptera: Noctuidae), one of important agricultural pests, has broken out more frequently in recent years. In this study, accumulation at different developmental stages and excretion of Cd were detected, and effect of cadmium (Cd concentrations were 0.2, 0.8, 3.2, 12.8, and 51.2 mg/kg, respectively) on three successive generations of beet armyworm was also studied using life table in the laboratory. Results showed that Cd2+ contents were significantly different when S. exigua was reared under different Cd2+ concentrations in the same generation in a significant dose-dependent manner. The concentration of Cd2+ increased with extension of stress time. Cd2+ concentration at different developmental stages was different, that is, larvae > pupa > adult. After emergence, Cd2+ concentration in both females and males decreased gradually, but that in paired adults decreased to a greater extent than that in unpaired ones. Beet armyworm could excrete heavy metals by means of faeces, prepupa exuviate, and puparium. Life table of the laboratory population was constructed, which showed that low doses of cadmium promoted the increase of population, whereas high doses inhibited the increase, meanwhile, with the extension of exposure length, the index of population trend (I) declined more rapidly. The study might provide references for the long-term and objective assessment of heavy metal pollution and its effect on the populations of important agricultural pests.

[Stress effects of imidacloprid on RSV in rice plants].

The rice stripe disease is a viral disease transmitted by small brown planthopper, Laodelphax striatellus, which outbroke a few years ago in the Yangtze River basin, especially Jiangsu region, China. To study the effects of imidacloprid stress on rice stripe virus (RSV) in rice plants, the rice seedlings were treated with imidacloprid 1, 2, 3 and 4 times (B1, B2, B3 and B4), respectively, after artificial inoculation by L. striatellus for 48 h, and the expression levels of relative genes including RSV NS3, CP, SP and NSvc4, as well as the protein concentrations of CP and SP were detected at different stages by real-time PCR and Western blotting. The results showed that the effects of imidacloprid treatment on the expression levels of four genes were gene-specific and correlated with application frequencies of imidacloprid. The expression levels of NS3 gene were upregulated in three treatments, and the highest expression level (10.86) was observed 16 days after inoculation in B4 treatment, but a significant down-regulation of NS3 gene was found in all other treatments. The expression levels of CP, SP and NSvc4 genes were down-regulated significantly (0-0.74) in almost all B2 and B3 treatments, while a significant up-regulation was found in half of B1 and B4 treatments, and the highest expression levels of SP gene were observed 16 days after inoculation in B1 (258.89) and B4 (730.54) treatment, respectively. On the other hand, the effects of imidacloprid stress on the expression patterns of CP and SP genes were different from those of CP and SP proteins. For example, the expression level of CP gene was almost no expression (0) 19 days after inoculation in B1 treatment, while significantly up-regulated (23.08) was observdd for CP protein.

Systemicity of chlorantraniliprole in velvetleaf (Abutilon theophrasti).

The systemicity of chlorantraniliprole was investigated and evidence was collected for formulating strategies in controlling vegetable or rice pests. Systemicity of chlorantraniliprole was investigated through chlorantraniliprole application on velvetleaf (Abutilon theophrasti) leaves as well as through hydroponic experiments. The roots of velvetleaf were incubated in chlorantraniliprole solution with a concentration of 50 microg/mL; the concentrations of chlorantraniliprole in xylem above the solution parts were 3.14, 5.67, and 6.89 microg/g at 24, 48, and 72 h after treatment. When the roots were incubated in chlorantraniliprole solution with a concentration of 200 microg/mL, the concentrations of chlorantraniliprole in xylem above the solution reached 6.48, 8.76, and 10.55 microg/g at 24, 48, and 72 h after treatment. Chlorantraniliprole was not detected in the phloem above the solution after these two treatments. When chlorantraniliprole solution with a concentration of 100 microg/mL was applied on mature leaves, chlorantraniliprole was found in xylem above the mature leaves at concentrations of 0.55, 0.74, and 0.92 microg/g at 24, 48, and 72 h after the treatment. No chlorantraniliprole was detected in the leaves below the mature leaves or the phloem above them. When chlorantraniliprole solution with a concentration of 100 microg/mL was applied on apical leaves, no chlorantraniliprole was detected in the xylem or phloem below them. These results indicated that chlorantraniliprole can be transported through xylem only upward, but chlorantraniliprole has no phloem mobility in velvetleaf.

[Effects of alcohol extracts from three kinds of biomass energy plant tissues on biological activity of Bemisia tabaci].

To test the feasibility of using raw extracts from the tissues of biomass energy plants Ricinus communi and Kosteletzkya virginica as plant protection agents, the alcohol extracts from R. communi seed and leaf and from K. virginica leaf were used to treat adult Bemisia tabaci by spraying. The glutathione S-transferase and carboxylesterase activities in B. tabaci body were measured after treated for 4 h, 24 h, 48 h, 72 h, and 96 h, and the olfaction responses of B. tabaci to the alcohol extracts were detected with a Y-tube olfactomet. All the three alcohol extracts obviously inhibited the glutathione S-transferase and carboxylesterase activities in a concentration-dependent manner. The inhibitory effect of the 250-times diluted alcohol extracts on the two enzyme activities was equivalent to that of 3000 times-diluted 1.8% avermectins. In addition, the 250-times diluted alcohol extracts had obvious repellent effect on B. tabaci, with the repellent coefficient of the alcohol extracts from R. communi seed and leaf and from K, virginica leaf being 100.0%, 96.7%, and 79.4%, respectively. All of these suggested that the test three alcohol extracts had repellent and other biological effects on B. tabaci.

[Bt toxic protein expression in insect-resistant transgenic corns and its transfer to and accumulation in Ostrinia furnacalis].

Taking the insect-resistant transgenic corn varieties G03-2396 and G03-2739 and the conventional corn variety Suyu 16 as test materials, a bioassay in laboratory was conducted to test their resistance against Ostrinia furnacalis. The Bt toxin expression in different tissues of the two transgenic corns, the ingestion of Bt toxin by the 3rd and 5th instar of O. furnacalis, and the Bt toxin amount in feces of O. furnacalis larvae fed with Bt corns were analyzed by using enzyme-linked-immunosorbent-assay (ELISA). It was found that the central leaves of both G03-2396 and G03-2739 had great toxicity to O. furnacalis larvae. After fed with the central leaves for 6 d, the survival rate of neonate larvae was less than 3%, and that of the 3rd instar larvae was less than 70%. Female ears had smaller toxicity than central leaves. The Bt toxic protein was detected both in the leaves and in the female ears of the two transgenic corns, but its content was higher in central leaves than in female ears. The Bt toxic protein expression level was in order of G03-2739 central leaf (39.6 microg x g(-1) FM) > G03-2396 central leaf (26.1 microg x g(-1) FM) > G03-2396 female ear (17.0 microg x g(-1) FM) > G03-2739 female ear (14.6 microg x g(-1) FM). When fed with central leaf or female ear, the Bt toxic protein amount in the 3rd instar larvae was significantly higher than that in the 5th instar larvae. For the same age instar larvae, the Bt toxic protein content was significantly higher after fed with central leaf than fed with female ear, so did the Bt toxic protein content in larvae feces, being the highest (10.4 microg x g(-1) FM) for the 5th instar larvae fed with G03-2739 central leaf, and the lowest (2.7 microg x g(-1) FM) for the 3rd instar larvae fed with G03-2739 female ear.