Relationship between deterrence and toxicity of plant secondary compounds for the alfalfa weevil Hypera brunneipennis

A variety of plant secondary compounds, several of which are quite widespread in nature were tested for their deterrence to the specialist coleopteran Hypera brunneipennis (Boheman) in short-term behavioral assays. The compounds were nicotine, quinine, sparteine, hordenine, linamarin, amygdalin, sinigrin, morin, juglone, chlorogenic acid, digitonin, mimosine, diosgenin, rutin and ursolic acid. Nine of these were then tested for their post-ingestional effects over one to two weeks of adult life, using fecundity as a measure of the effects. In only one case was there any indication of a detrimental effect or any trend suggesting one. The evolutionary implications of these findings are discussed.     

A study of behavioural habituation to a feeding deterrent in nymphs of Schistocerca gregaria

ABSTRACT. Behavioural habituation† of Schistocerca gregaria Forskål fifth instar larvae to a feeding deterrent, nicotine hydrogen tartrate (NHT), is described. An attempt was made to differentiate between various factors possibly involved in the induction of this behavioural habituation. Sensory stimulation (through maxillary palp), cannulation of NHT into the crop, and its administration by gelatine capsules placed into the oesophagus each resulted in behavioural habituation, but in the latter two cases a sole induction via post-ingestional input is not completely proven. Injection of NHT into the haemolymph did not induce habituation. It is concluded that habituation via sensory stimulation is a central phenomenon.     

Potential for habituation to a neem-based feeding deterrent in Japanese beetles, Popillia japonica

We tested the potential for the Japanese beetle, Popillia japonica Newman, to habituate to a neem-based feeding deterrent applied to foliage of linden, Tilia cordata L., a preferred host for the adults. Female beetles' consumption of control foliage versus foliage treated with either a low or high rate of neem insecticide, corresponding to 9 or 39 pm azadirachtin, respectively, was tested in a series of 4-h choice or no-choice tests over four successive days. In another experiment, females were conditioned for 22 h with either control foliage, leaves treated with the low rate, or a mixture of both treated and untreated leaves. Deterrence of either the low or high rate of neem to these beetles was then evaluated in choice tests with control foliage, as before. In choice tests, mean consumption of control foliage was always greater than for treated foliage, regardless of rate. There was, however, proportionately more feeding on foliage treated with the high rate upon successive exposures. In no-choice tests, beetles initially deterred by the low rate were not significantly deterred by that rate by the third and fourth days of the experiment. Finally, beetles conditioned by exposure to leaves treated with the low rate were not deterred by that rate in a subsequent choice test, although they were deterred by the higher rate. Despite these trends, we suggest that Japanese beetles' polyphagy and mobility probably would reduce the likelihood for habituation to neem-based feeding deterrents in the field.     

Insect feeding deterrent property of alantolactone

The sesquiterpene lactone, alantolactone, significantly reduces feeding and survival of Tribolium confusum. These findings support the view that alantolactone may protect plants such as composites from insect attack.     

不同昆虫寄主对昆虫病原线虫共生菌的敏感性比较

用菜青虫、棉铃虫、甜菜夜蛾、玉米螟、粘虫、黄粉虫等 6种昆虫对 1 0株昆虫病原线虫共生菌进行了敏感性测定。结果表明 :供试菌株对 6种昆虫都有胃毒活性 ,不同菌株对同一种昆虫的毒力差别较大 ,同一菌株对不同昆虫差别也很大。 1 0株菌在 1 2 0h对菜青虫的校正死亡率和体重抑制率均最高 ,显然是最敏感的寄主。在 1 0株共生菌中 ,XenorhabdusnematophilaHB3 1 0 5 9菌株的胃毒活性最高。     

Insecticidal and feeding deterrent activities of essential oils in the cabbage looper,Trichoplusia ni (Lepidoptera: Noctuidae)

Ten essential oils were tested against the cabbage looper, Trichoplusia ni larvae for contact, residual and fumigant toxicities and feeding deterrent effects. Against third instar T. ni, Syzygium aromaticum (LD₅₀ = 47.8 μg/larva), Thymus vulgaris (LD₅₀ = 52.0 μg/larva) (the two positive controls) and Cinnamomum glanduliferum (LD₅₀ = 76.0 μg/larva) were the most toxic via topical application. Litsea pungens (LD₅₀ = 87.1 μg/larva), Ilex purpurea (LD₅₀ = 94.0 μg/larva), Cinnamomum cassia (LD₅₀ = 101.5 μg/larva) and Litsea cubeba (LD₅₀ = 112.4 μg/larva) oils were equitoxic. Thymus vulgaris (LC₅₀ = 4.8 mg/ml) and S. aromaticum (LC₅₀ = 6.0 mg/ml) oils were the most toxic in residual bioassays. Cymbopogon citratus (LC₅₀ = 7.7 mg/ml) and C. cassia (LC₅₀ = 8.5 mg/ml) oils were equitoxic followed by Cymbopogon nardus (LC₅₀ = 10.1 mg/ml) in this bioassay. The remaining five oils showed little or no residual effects. In a fumigation bioassay, L. cubeba (LC₅₀ = 16.5 μl/l) and I. purpurea (LC₅₀ = 22.2 μl/l) oils were the most toxic. Cinnamomum glanduliferum (LC₅₀ = 29.7 μl/l) and Sabina vulgaris (LC₅₀ = 31.2 μl/l) oils were equitoxic. Interestingly, S. aromaticum did not exhibit any fumigant toxicity. Cymbopogon citratus, C. nardus and C. cassia strongly deterred feeding by third instar T. ni (DC₅₀s = 26.9, 33.8 and 39.6 μg/cm², respectively) in a leaf disc choice bioassay. The different responses of T. ni larvae to the oils in different bioassays suggest that these essential oils exhibit different modes of action. Based on their comparable efficacy with essential oils already used as active ingredients in many commercial insecticides (i.e. clove oil and thyme oil), some of these essential oils may have potential as botanical insecticides against T. ni.     

Insect feeding deterrent activity of phytoalexin isoflavonoids

When incorporated into an agar-cellulose medium containing feeding stimulants, phytoalexin isoflavonoids from several legumes show feeding deterrent activity against larvae of the insect Costelytra zealandica and Heteronychus arator. The levels at which these compounds deter feeding are of the same order of magnitude as those at which they reduce fungal growth. The most active compound tested was phaseollin. These results suggest that phytoalexin isoflavonoids show a dual acitvity against insects and fungi.     

小菜蛾经历"保卫德"后产卵选择行为的变化

植食性昆虫成虫对非寄主植物源驱避素的经历,可导致其对这类化合物产生习惯性反应或诱导嗜好性.让小菜蛾雌蛾对源于印楝的驱避剂——“保卫德”(BIOACT-T^TM EC508)经历2～6次或2～6日后,测定它们对经过保卫德处理的白菜植株的产卵选择行为.结果表明,保卫德对2日龄、4日龄、6日龄无经历雌蛾均有很强的驱避作用,它们在经过保卫德处理的白菜植株上的相对产卵率均只有10%左右;对保卫德有2次或2 d经历的2日龄雌蛾,该产卵率平均上升到17%;对保卫德有4次或4 d经历的4日龄雌蛾,该产卵率上升到21%～24%;对保卫德有6次或6 d经历的6日龄雌蛾,该产卵率上升到29%.表明经历可导致雌蛾对保卫德产生习惯性反应或诱导嗜好性,使保卫德的驱避作用下降,但这种经历导致的产卵选择行为变化在个体之间存在较大差异.     

Feeding deterrent response of corn insects to β-exotoxin of Bacillus thuringiensis

Exotoxins produced by three varieties of Bacillus thuringiensis were added at different concentrations to the diets of the black cutworm, the fall armyworm, the European corn borer, and the house fly. By day 7 of treatment, mortality of the three lepidopterans was higher at the lower concentrations of exotoxin than at the higher concentrations tested; by day 14 of treatment, mortality was 90% of greater at all the exotoxin concentrations tested. In the house fly tests, mortality increased with increasing exotoxin concentration. Additional lepidopteran tests were run to study both the anomalous effect of toxin concentration on mortality and the effect of feeding inhibition evident by day 7 but not day 14 in treatments with high concentrations of the toxins. The tests, run with the European corn borer and with β-exotoxin calcium salt, showed that both effects could be attributed to a “feeding deterrent” associated with the toxin, and that the deterrent was not odoriforous and did not degrade over time. Apparently, the insects ate very little of the diets high in exotoxin, stopping quickly upon receiving a high dosage of the deterrent, but, nevertheless, having consumed enough toxin to be killed over time (between 7 and 14 days).     

Oral dosing of neonatal mice with sucrose reduces infection with Cryptosporidium parvum

Cryptosporidium parvum is a significant cause of diarrheal disease in humans and economically important livestock species. There is no effective treatment available for this protozoan parasite. Mechanisms of intestinal colonization by C. parvum are not well understood, but it has been suggested that the parasite may utilize a lectin-like receptor. We used an infant mouse model to test whether high sugar concentrations in the intestine would affect in vivo colonization with C. parvum. We found that a single oral dose of sucrose, administered to mice at the time of, or 24 hr before, challenge with C. parvum significantly reduced infection. Significant reduction of infection was also seen in mice given isomaltose. Histologic examination of intestinal sections of mice treated with sucrose or isomaltose, but not other sugars, showed marked vacuolation of the small intestinal epithelium 1 day after treatment. Three days after treatment, tissue appeared normal. Thus, sucrose and, to a lesser extent, isomaltose reduced in vivo colonization with C. parvum and altered epithelial cell morphology in intestines of mice.     

金蛇胆口服液急性毒性及镇咳抗炎药效研究

研究金蛇胆口服液的毒性及镇咳抗炎作用。方法给小鼠灌胃。结果金蛇胆口服液无急性毒性反应,能明显抑制二甲苯诱发的小鼠耳壳肿胀。能延长氨水所致小鼠咳嗽潜伏期,减少咳嗽次数。     

Insect feeding deterrent activity of bisabolangelone and of some sesquiterpenes of eremophilane type

The insect feeding deterrent activity of some sesquiterpenes of furanoeremophilane type and of the related eremophilanolide type were tested towards three selected storage pests: Sitophilus granarius, Tribolium confusum and Trogoderma granarium. The results were compared with the biogenetically related compound of bakkenolide type, known as a potent antifeedant. Bisabolangelone, tested on the same insects, exhibited the strongest activity, and may be included in the class of very good insect feeding deterrents. The antifeeding activity of bisabolangelone and bakkenolide A towards larvae of Leptinotarsa decemlineata was also observed.     

Insect feeding deterrent activity of lignans and related phenylpropanoids with a methylenedioxyphenyl (piperonyl) structure moiety

The antifeedant activity of a series of lignan lactones, hemiacetals, ethers, and alcohols derived from yatein and cubebin, together with structurally related phenylpropanoids and phenolics possessing a methylenedioxyphenyl (piperonyl) moiety, was tested against selected stored products pests: Sitophilus granarius L. (Coleoptera: Curculionidae), Tribolium confusum Duv. (Coleoptera: Tenebrionideae), and Trogoderma granarium Ev. (Coleoptera: Dermestridae). The relation between molecular structure and antifeedant activity was examined and implication of the piperonyl moiety is assessed. The compounds represent either natural substances isolated from plants (Libocedrus yateensis Guillaumin and Piper cubeba L.) or their structural analogues prepared by simple chemical transformations as well as compounds selected from commercially available sources. Natural lignan lactones with methoxy and/or methylenedioxy substituents showed significant activity that is strong enough to affect plant - insect interactions. Presence of polar substituents, especially hydroxy or glycosyl groups, often reduce the activity. Non-polar substituents, such as methoxy or methylenedioxy groups, enhance the activity not only in lignans but also in simple phenylpropanoids. The most active compound was synthetic piperonylbutoxide.     

30天喂养试验中不同受试方法对SD大鼠生理指标的影响

目的 了解在30 d喂养试验中不同受试方法引起SD大鼠生理指标的变化,建立实验室质量控制体系.方法 采用自由饮水、蒸馏水灌胃、食用植物油灌胃3种方法,记录在30 d喂养试验中SD大鼠的体重、进食量、脏体重、血液学及生化值,计算食物利用率、脏体比.结果 经18份检品报告中的360只大鼠食用植物油灌胃比自由饮水动物周体重、周进食量、脏体湿重显著偏低,相应总增重、总进食量、总食物利用率显著偏低;血液学检测值雌、雄鼠各组间无差异;生化检测值差异大,雄鼠血糖显著偏低,雌、雄鼠甘油三酯显著偏高.蒸馏水灌胃与自由饮水组相比各生理生化值无差异.结论 30 d喂养试验中,3种不同受试方法可行,SD大鼠生理指标值波动范围较大,均在许可范围内.认为可作为实验室质量控制指标,为研制实验动物生理指标值提供科学依据.     

Perception of noxious compounds by contact chemoreceptors of the blowfly,Phormia regina: putative role of an odorant-bindingpProtein

The blowfly, Phormia regina, has sensilla with four contact-chemoreceptor cells and one mechanoreceptor cell on its labellum. Three of the four chemoreceptor cells are called the sugar, the salt and the water receptor cells, respectively. However, the specificity of the remaining chemoreceptor cell, traditionally called the "fifth cell", has not yet been clarified. Referring to behavioral evaluation of the oral toxicity of monoterpenes, we measured the electrophysiological response of the "fifth cell" to these compounds. Of all the monoterpenes examined, D-limonene exhibited the strongest oral toxicity and induced the severest aversive behavior with vomiting and/or excretion in the fly. D-Limonene, when dispersed in an aqueous stimulus solution including dimethyl sulfoxide or an odorant-binding protein (OBP) found in the contact-chemoreceptor sensillum, the chemical sense-related lipophilic ligand-binding protein (CRLBP), evoked impulses from the "fifth cell". Considering the relationship between the aversive effects of monoterpenes and the response of the "fifth cell" to these effects, we propose that the "fifth cell" is a warning cell that has been differentiated as a taste system for detecting and avoiding dangerous foods. Here we suggest that in the insect contact-chemoreceptor sensillum, CRLBP carries lipophilic members of the noxious taste substances to the "fifth cell" through the aqueous sensillum lymph. This insect OBP may functionally be analogous to the von Ebner's grand protein in taste organs of mammals.     

Sialic acids in the salivary glands of some insects with different feeding habits

Summary Eight insects (some adult and some larval forms) are studied for the presence of sialic acids in the cells of the salivary glands. This was sought by staining with alcian blue and Azure A at different pH accompanied by acid hydrolysis, sialidase digestion and methylation-saponification.On the basis of susceptibility to acid hydrolysis and sialidase digestion, different sialic acids are discernable. Though there is apparently no correlation between the secretion of sialic acid and the feeding habits of these insects, there is an interesting correlation between these two in the case of nectar and pollen eating habit of Apis.Presented at the 56th Session of Indian Science Congress. 2–9 January, 1969, Bombay, India.     

Oral microcirculation in post-menopause: a possible correlation with periodontitis

doi: 10.1111/j.1741‐2358.2011.00608.x Oral microcirculation in post‐menopause: a possible correlation with periodontitis Objectives: The reduction in the level of oestrogen, typical in menopause, has some effect on the health of the oral cavity. In fact, post‐menopausal women present more severe periodontal disease than pre‐menopausal women. Numerous factors can be held to be responsible for this increase, among which are the effects of oestrogens on the oral epithelium, on the salivary glands, on bone tissue and on the endothelium. Our double blind study aims to evaluate the possible variations in oral microcirculation in post‐menopausal women. Methods: Twenty‐seven women in post‐menopause (age: Mean ± SD: 57.3 ± 8.73) and 27 women in pre‐menopause (age: Mean ± SD: 27.77 ± 3.56) were examined. Oral microcirculation was investigated using oral videocapillaroscopy. Results: The study showed significant differences between cases and controls for the following parameters: decrease in diameter of loops (mean ± SD: 0.038 ± 0.008; 0.045 ± 0.005), increase in tortuosity (mean ± SD: 3.83 ± 1.13; 1.83 ± 1.06) in labial mucosa and decrease in density in periodontal mucosa (Mean ± SD: 28.86 ± 10.92; 89.62 ± 17.83). Conclusion: The decrease in periodontal density may compromise the epithelium tropism, making it prone to inflammation. The tortuosity may indicate a greater permanence of inflammatory factors, increased in post‐menopausal women.     

Prediction of non-genotoxic carcinogenesis in rats using changes in gene expression following acute dosing

Non-genotoxic carcinogenicity of chemicals is currently routinely evaluated in 2-year rodent bioassays. Therefore, the development of early biomarkers for non-genotoxic carcinogenesis would result in substantial savings in time and expense. The current study investigates whether early changes in gene expression may be developed as markers for cancer. Animals were treated for 1 or 5 days with either non-genotoxic carcinogens (NGTCs) or non-carcinogens and gene expression was analyzed by quantitative PCR (qPCR). We tested two gene signatures previously reported to detect non-genotoxic carcinogens. Using one gene signature it was confirmed that 3/3 non-genotoxic carcinogens and 2/2 non-carcinogens are correctly identified with data from 1 or 5 days of dosing. In contrast an alternative signature correctly identified 0/3 and 2/3 non-genotoxic carcinogens at 1 and 5 days of treatment, respectively and 2/2 non-carcinogens at both time-points. Additionally, we evaluated a novel panel of putative biomarker genes, from the literature, many of which have roles in cell growth and division, including myc, cdc2 and mcm6. These genes were significantly induced by non-genotoxic carcinogens and not by non-carcinogens. Using the average fold-induction across this panel, 2/3 non-genotoxic carcinogens were detected at both 1 and 5 days. These data support the idea that acute changes in gene expression may provide biomarkers for non-genotoxic carcinogenesis but also highlight interesting differences in the sensitivities of distinct gene signatures.