Preference and performance of peach fruit fly (Bactrocera Zonata) and Melon fruit fly (Bactrocera Cucurbitae) under laboratory conditions

In Pakistan and all over the world, the Peach Fruit Fly (PFF), Bactrocera zonata (Saunders.) and the Melon Fruit Fly (MFF), Bactrocera cucurbitae (Coquillett.) are considered severe and polyphagous insect pests for various fruits and vegetables. The current study was conducted to check the Laboratory preference and performance of B. cucurbitae and B. zonata on selected Fruits Citrus (Citrus sinensis), Apple (Malus domestica), Banana (Musa acuminate), and vegetable, Sponge gourd (luffa aegyptiaca), Bitter gourd (Momordica charantia) Pumpkin (Cucurbita moschata) under laboratory conditions. The study showed that Sponge Gourd was the preferable host with the mean pupae resurgence of (242.33), followed by Bitter Gourd (78.333) among selected vegetables. At the same time, among fruits, a banana was the preferable host with mean pupae resurgence (204.33), followed by orange (158.33). The pumpkin and apple was the least preferable host for both B. cucurbitae and B. zonata, with mean pupae resurgence (35.667) and (79.000), respectively. Furthermore, the study showed that Banana was the preferable host for B. Zonata among intact and infested fruits, whereas B. cucurbitaee showed the most preference to Bitter gourd among intact and infested vegetables showing significantly different results among intact and infested fruits and vegetables. Maximum number of eggs, pupa, female flies, male flies, adult emergence from pupa (flies) and period of pupa of B. zonata and B. cucurbitae on banana and bitter gourd. While, other fruits and vegetables showed the minimum number of eggs, pupa, female flies, male flies, adult emergence from pupa (flies) and period of the pupa. The current study concluded there is a need to evaluate other host plants against these fruit fly species for effective control.     

Management of Bittergourd yellow mosaic virus (BGYMV) by using virus inhibiting chemical,biocontrol agents,antiviral principles (AVP) and insecticide

Abstract

Bitter gourd Yellow Mosaic Virus (BGYMV) is a Whitefly transmitted geminivirus. BGYMV causes yellow mosaic disease in bitter gourd. This disease attains significance because the virus causing this disease is capable of attacking the crop at all stages. There was a severe yield loss in bitter gourd plants due to the infection of BGYMV. Bitter gourd plants treated with Bougainvillea spectabilis challenge inoculated with BGYMV reduced the disease incidence and increased the plant growth. In the above treatment the disease incidence was 33.33% at 75 Days After Sowing (DAS). But in the inoculated untreated control the disease incidence was 100% at 75 DAS. The mean maximum plant height was 92.24 cm in plants inoculated at 65 DAS. Bougainvillea spectabilis treated plants challenge inoculated with BGYMV showed an increased activity of peroxidase, polyphenoloxidase and phenol content from 4 Days After Inoculation (DAI) to 12 DAI. The activity of all the enzymes was reduced from 16 DAI in all the treatments.     

Increased dopaminergic signaling impairs aversive olfactory memory retention in Drosophila

Dopamine is necessary for the aversive olfactory associative memory formation in Drosophila, but its effect on other stages of memory is not known. Herein, we studied the effect of enhanced dopaminergic signaling on aversive olfactory memory retention in flies. We used l-3,4-dihydroxyphenylalanine (l-DOPA) to elevate dopamine levels: l-DOPA-treated flies exhibited a normal learning performance, but a decrease in 1-h memory. Dopamine transporter (DAT) mutant flies or flies treated with the DAT inhibitor desipramine exhibited poor memory retention. Flies subjected to heat stress after training exhibited a decrease in memory. Memory was restored by blocking dopaminergic neuronal output during heat stress, suggesting that dopamine is involved in heat stress-induced memory impairment in flies. Taken together, our findings suggest that increased dopaminergic signaling impairs aversive olfactory memory retention in flies.     

Social Environment Influences Performance in a Cognitive Task in Natural Variants of the Foraging Gene

In Drosophila melanogaster, natural genetic variation in the foraging gene affects the foraging behaviour of larval and adult flies, larval reward learning, adult visual learning, and adult aversive training tasks. Sitters (for ^s) are more sedentary and aggregate within food patches whereas rovers (for^R) have greater movement within and between food patches, suggesting that these natural variants are likely to experience different social environments. We hypothesized that social context would differentially influence rover and sitter behaviour in a cognitive task. We measured adult rover and sitter performance in a classical olfactory training test in groups and alone. All flies were reared in groups, but fly training and testing were done alone and in groups. Sitters trained and tested in a group had significantly higher learning performances compared to sitters trained and tested alone. Rovers performed similarly when trained and tested alone and in a group. In other words, rovers learning ability is independent of group training and testing. This suggests that sitters may be more sensitive to the social context than rovers. These differences in learning performance can be altered by pharmacological manipulations of PKG activity levels, the foraging (for) gene''s gene product. Learning and memory is also affected by the type of social interaction (being in a group of the same strain or in a group of a different strain) in rovers, but not in sitters. These results suggest that for mediates social learning and memory in D. melanogaster.     

Differences in body size and egg loads of Rhagoletis indifferens (Diptera: Tephritidae) from introduced and native cherries

The western cherry fruit fly, Rhagoletis indifferens Curran, infests introduced, domesticated sweet [Prunus avium (L.) L.], and tart cherries (Prunus cerasus L.) as well as native bitter cherry, Prunus emarginata (Douglas) Eaton. Bitter cherries are smaller than sweet and tart cherries and this could affect various life history traits of flies. The objectives of the current study were to determine 1) if body size and egg loads of flies infesting sweet, tart, and bitter cherries differ from one another; and 2) if any observed body size differences are genetically based or caused by the host fruit environment. Pupae and adults of both sexes reared from larval-infested sweet and tart cherries collected in Washington and Montana were larger than those reared from bitter cherries. In addition, flies of both sexes caught on traps in sweet and tart cherry trees were larger than those caught in bitter cherry trees and females trapped from sweet and tart cherry trees had 54.0-98.8% more eggs. The progeny of flies from naturally-infested sweet and bitter cherries reared for one generation in the laboratory on sweet cherry did not differ in size. The same also was true for progeny of sweet and bitter cherry flies reared in the field on bitter cherry. The results suggest that the larger body sizes of flies from sweet and tart cherries than bitter cherries in the field are caused by host fruit and not genetic factors.     

Bitter gourd (Momordica charantia) is a cornucopia of health: a review of its credited antidiabetic, anti-HIV, and antitumor properties

Bitter gourd (Momordica charantia, BG) is both a nutritious and healthy food with a distinctive bitter flavor, and it is also widely exploited in folklore medicine. This review focuses on the efficacies and molecular mechanisms of BG-induced anti-diabetic, anti-HIV, and antitumor activities contributed by over twenty active components. The intent of this review is to provide comprehensive and valuable information for medicinal researchers, drug investigators, clinicians, and even patients with an interest in BG. In conclusion, BG is a cornucopia of health and it deserves in-depth investigations for clinical application in the future.     

Experimental evolution of olfactory memory in Drosophila melanogaster

In order to address the nature of genetic variation in learning performance, we investigated the response to classical olfactory conditioning in "high-learning" Drosophila melanogaster lines previously subject to selection for the ability to learn an association between the flavor of an oviposition medium and bitter taste. In a T-maze choice test, the seven high-learning lines were better at avoiding an odor previously associated with aversive mechanical shock than were five unselected "low-learning" lines originating from the same natural population. Thus, the evolved improvement in learning ability of high-learning lines generalized to another aversion learning task involving a different aversive stimulus (shock instead of bitter taste) and a different behavioral context than that used to impose selection. In this olfactory shock task, the high-learning lines showed improvements in the learning rate as well as in two forms of consolidated memory: anesthesia-resistant memory and long-term memory. Thus, genetic variation underlying the experimental evolution of learning performance in the high-learning lines affected several phases of memory formation in the course of olfactory aversive learning. However, the two forms of consolidated memory were negatively correlated among replicate high-learning lines, which is consistent with a recent hypothesis that these two forms of consolidated memory are antagonistic.     

Investigating the effect of emetic compounds on chemotaxis in Dictyostelium identifies a non-sentient model for bitter and hot tastant research

Novel chemical entities (NCEs) may be investigated for emetic liability in a range of unpleasant experiments involving retching, vomiting or conditioned taste aversion/food avoidance in sentient animals. We have used a range of compounds with known emetic /aversive properties to examine the possibility of using the social amoeba, Dictyostelium discoideum, for research into identifying and understanding emetic liability, and hence reduce adverse animal experimentation in this area. Twenty eight emetic or taste aversive compounds were employed to investigate the acute (10 min) effect of compounds on Dictyostelium cell behaviour (shape, speed and direction of movement) in a shallow chemotaxic gradient (Dunn chamber). Compound concentrations were chosen based on those previously reported to be emetic or aversive in in vivo studies and results were recorded and quantified by automated image analysis. Dictyostelium cell motility was rapidly and strongly inhibited by four structurally distinct tastants (three bitter tasting compounds--denatonium benzoate, quinine hydrochloride, phenylthiourea, and the pungent constituent of chilli peppers--capsaicin). In addition, stomach irritants (copper chloride and copper sulphate), and a phosphodiesterase IV inhibitor also rapidly blocked movement. A concentration-dependant relationship was established for five of these compounds, showing potency of inhibition as capsaicin (IC(50) = 11.9 ± 4.0 μM) > quinine hydrochloride (IC(50) = 44.3 ± 6.8 μM) > denatonium benzoate (IC(50) = 129 ± 4 μM) > phenylthiourea (IC(50) = 366 ± 5 μM) > copper sulphate (IC(50) = 1433 ± 3 μM). In contrast, 21 compounds within the cytotoxic and receptor agonist/antagonist classes did not affect cell behaviour. Further analysis of bitter and pungent compounds showed that the effect on cell behaviour was reversible and not cytotoxic, suggesting an uncharacterised molecular mechanism of action for these compounds. These results therefore demonstrate that Dictyostelium has potential as a non-sentient model in the analysis of the molecular effects of tastants, although it has limited utility in identification of emetic agents in general.     

Distinct traces for appetitive versus aversive olfactory memories in DPM neurons of Drosophila

The global logic used by the brain for differentially encoding positive and negative experiences remains unknown along with how such experiences are represented by collections of memory traces at the cellular level. Here we contrast the cellular memory traces that form in the dorsal paired medial (DPM) neurons of Drosophila after conditioning flies with odors associated with aversive or appetitive unconditioned stimuli (US). Our results show that the appetitive DPM neuron trace is distinguished from the aversive in three fundamental ways: (1) The DPM neurons do not respond to an appetitive US of sucrose by itself, in contrast to their robust response to an aversive US. (2) The appetitive trace persists for twice as long as the aversive trace. (3) The appetitive trace is expressed in both neurite branches of the neuron, rather than being confined to a single branch like the aversive trace. In addition, we demonstrate that training flies with nonnutritive sugars that elicit a behavioral memory that decays within 24 hr generates, like aversive conditioning, a short-lived and branch-restricted memory trace. These results indicate that the persistence and breadth of the DPM neuron memory trace influences the duration of behavioral memory.     

Drosophila Fatty Acid Taste Signals through the PLC Pathway in Sugar-Sensing Neurons

Taste is the primary sensory system for detecting food quality and palatability. Drosophila detects five distinct taste modalities that include sweet, bitter, salt, water, and the taste of carbonation. Of these, sweet-sensing neurons appear to have utility for the detection of nutritionally rich food while bitter-sensing neurons signal toxicity and confer repulsion. Growing evidence in mammals suggests that taste for fatty acids (FAs) signals the presence of dietary lipids and promotes feeding. While flies appear to be attracted to fatty acids, the neural basis for fatty acid detection and attraction are unclear. Here, we demonstrate that a range of FAs are detected by the fly gustatory system and elicit a robust feeding response. Flies lacking olfactory organs respond robustly to FAs, confirming that FA attraction is mediated through the gustatory system. Furthermore, flies detect FAs independent of pH, suggesting the molecular basis for FA taste is not due to acidity. We show that low and medium concentrations of FAs serve as an appetitive signal and they are detected exclusively through the same subset of neurons that sense appetitive sweet substances, including most sugars. In mammals, taste perception of sweet and bitter substances is dependent on phospholipase C (PLC) signaling in specialized taste buds. We find that flies mutant for norpA, a Drosophila ortholog of PLC, fail to respond to FAs. Intriguingly, norpA mutants respond normally to other tastants, including sucrose and yeast. The defect of norpA mutants can be rescued by selectively restoring norpA expression in sweet-sensing neurons, corroborating that FAs signal through sweet-sensing neurons, and suggesting PLC signaling in the gustatory system is specifically involved in FA taste. Taken together, these findings reveal that PLC function in Drosophila sweet-sensing neurons is a conserved molecular signaling pathway that confers attraction to fatty acids.     

Use of bitter gourd (Momordica charantia) peroxidase together with redox mediators to decolorize disperse dyes

In this study, salt fractionated bitter gourd (Momordica charantia) peroxidase was used for the decolorization of water-insoluble disperse dyes; Disperse Red 17 and Disperse Brown 1. Effect of nine different redox mediators; bromophenol, 2,4-dichlorophenol, guaiacol, 1-hydroxybenzotriazole, m-cresol, quinol, syringaldehyde, violuric acid, and vanillin on decolorization of disperse dyes by bitter gourd peroxidase has been investigated. Among these redox mediators, 1-hydroxybenzotriazole was the most effective mediator for decolorization of both the dyes by peroxidase. Bitter gourd peroxidase (0.36 U/mL) could decolorize Disperse Red 17 maximally 90% in the presence of 0.1 mM 1-hydroxybenzotriazole while Disperse Brown 1 was decolorized 65% in the presence of 0.2 mM 1-hydroxybenzotriazole. Maximum decolorization of these dyes was obtained within 1 h of incubation at pH 3.0 and temperature 40°C. The application of such enzyme plus redox mediator systems may be extendable to other recalcitrant and water insoluble synthetic dyes using novel redox mediators and peroxidases from other new and cheaper sources.     

Variability in the production of amylase by three isolates ofMyrothecium roridum

Amylase production by three isolates ofMyrothecium roridum under different cultural conditions was studied. Starch followed by dextrin induced maximum amylase production (dextrinizing and saccharifying) by all the three isolates. Glucose was a poor substrate for the production of amylases. Bitter gourd isolate was a comparatively more efficient producer of amylases than the other two isolates. Addition of glucose to the starch medium resulted in a repression of amylases. Urea was a good source of nitrogen for induction of dextrinizing amylase in bitter gourd and pearl millet isolates.l-Asparagine,l-tyrosine were good sources of nitrogen for induction of saccharifying amylase in bitter gourd, water melon and pearl millet isolate, respectively. With a few exceptions, dextrinizing amylase production was inhibited by gibberellic acid, cycocel, calcium chloride and calcium sulfate, while these substances stimulated saccharifying-amylase production. No correlation could be observed between amylase production and vegetative growth. Amylases of all the three isolates ofM. roridum were characterized.     

Fruit flies learn to avoid odours associated with virulent infection

While learning to avoid toxic food is common in mammals and occurs in some insects, learning to avoid cues associated with infectious pathogens has received little attention. We demonstrate that Drosophila melanogaster show olfactory learning in response to infection with their virulent intestinal pathogen Pseudomonas entomophila. This pathogen was not aversive to taste when added to food. Nonetheless, flies exposed for 3 h to food laced with P. entomophila, and scented with an odorant, became subsequently less likely to choose this odorant than flies exposed to pathogen-laced food scented with another odorant. No such effect occurred after an otherwise identical treatment with an avirulent mutant of P. entomophila, indicating that the response is mediated by pathogen virulence. These results demonstrate that a virulent pathogen infection can act as an aversive unconditioned stimulus which flies can associate with food odours, and thus become less attracted to pathogen-contaminated food.     

产紫篮状菌的生防潜力及其对土壤微生物群落的调控

产紫篮状菌Q2菌株是一株分离自健康黄瓜根际的有益微生物。本文通过平皿对峙培养、温室盆栽试验和田间试验评估了Q2菌株对4种土传病害的生防潜力及其与土壤熏蒸技术结合对苦瓜枯萎病的防治效果,并通过平皿稀释培养法、高通量技术和定量PCR技术对其防治苦瓜枯萎病及调控土壤微生物群落的机制进行研究。结果表明: 在温室条件下,Q2菌株对苦瓜枯萎病、烟草黑胫病、烟草根黑腐病和马铃薯茎基腐病具有明显的预防效果,对烟草黑胫病和苦瓜枯萎病防治效果分别达到75.3%和63.4%。在苦瓜枯萎病人工病圃中,单一产紫篮状菌Q2制剂对苦瓜枯萎病的防治效果为51.0%,其结合威百亩土壤熏蒸技术在相同试验条件下对枯萎病的防治效果则达到80%以上。威百亩土壤熏蒸显著降低了土壤中苦瓜枯萎病病原菌即尖镰孢菌的丰度,而Q2菌株有效地抑制了尖镰孢菌数量的恢复趋势。施用Q2菌株显著富集了土壤中的青霉菌、芽孢杆菌和Gaiella等有益微生物,抑制了尖镰孢菌的恢复。土壤熏蒸后,施用产紫篮状菌Q2菌株有助于土壤有益微生物菌群的形成,从而抑制尖镰孢菌,实现对苦瓜枯萎病的防治。     

Bitter peptides activate hTAS2Rs, the human bitter receptors

Fermented food contains numerous peptides derived from material proteins. Bitter peptides formed during the fermentation process are responsible for the bitter taste of fermented food. We investigated whether human bitter receptors (hTAS2Rs) recognize bitterness of peptides with a heterologous expression system. HEK293 cells expressing hTAS2R1, hTAS2R4, hTAS2R14, and hTAS2R16 responded to bitter casein digests. Among those cells, the hTAS2R1-expressing cell was most strongly activated by the synthesized bitter peptides Gly-Phe and Gly-Leu, and none of the cells was activated by the non-bitter dipeptide Gly-Gly. The results showed that these bitter peptides, as well as many other bitter compounds, activate hTAS2Rs, suggesting that humans utilize these hTAS2Rs to recognize and perceive the structure and bitterness of peptides.     

Central mechanisms of roles of taste in reward and eating

Taste is unique among sensory systems in its innate association with mechanisms of reward and aversion in addition to its recognition of quality, e.g., sucrose is sweet and preferable, and quinine is bitter and aversive. Taste information is sent to the reward system and feeding center via the prefrontal cortices such as the mediodorsal and ventrolateral prefrontal cortices in rodents and the orbitofrontal cortex in primates. The amygdala, which receives taste inputs, also influences reward and feeding. In terms of neuroactive substances, palatability is closely related to benzodiazepine derivatives and beta-endorphin, both of which facilitate consumption of food and fluid. The reward system contains the ventral tegmental area, nucleus accumbens and ventral pallidum and finally sends information to the lateral hypothalamic area, the feeding center. The dopaminergic system originating from the ventral tegmental area mediates the motivation to consume palatable food. The actual ingestive behavior is promoted by the orexigenic neuropeptides from the hypothalamus. Even palatable food can become aversive and avoided as a consequence of a postingestional unpleasant experience such as malaise. The neural mechanisms of this conditioned taste aversion will also be elucidated.     

The effect of silicon on the infection by and spread of Pythium aphanidermatum in single roots of tomato and bitter gourd

The effect of silicon (Si) supply on the infection and spread of Pythium aphanidermatum was studied in the roots of tomato [Lycopersicon esculentum (=Solanum lycopersicum), an Si excluder] and bitter gourd (Mormodica charantia, an Si intermediate accumulator). Individual roots were mounted into PVC compartmented boxes which allowed the application of Si and zoospores to defined root zones. Two days after inoculation, root growth was recorded, and P. aphanidermatum colonization of individual root sections was determined by ELISA. In tomato as well as in bitter gourd the root tip was the root section most sensitive to P. aphanidermatum infection. Application of Si did not affect severe root-growth inhibition by P. aphanidermatum in either species. However, continuous Si supply significantly inhibited the basipetal spread of the pathogen from the infected root apex in bitter gourd but not in tomato. Si application to the roots only during pretreatment or only during/after the infection of the roots failed to inhibit the spread of P. aphanidermatum. Determination and compartmentation of Si in the roots of bitter gourd revealed that apoplastic Si was not, but symplastic Si was, associated with the ability of the plant to reduce the spread of the fungus in roots. It is concluded that accumulation of Si in the root cell walls does not represent a physical barrier to the spread of P. aphanidermatum in bitter gourd and tomato roots. The maintenance of elevated symplastic Si contents is a prerequisite for Si-enhanced resistance against P. aphanidermatum.     

Identification of Communal Oviposition Pheromones from the Black Fly Simulium vittatum

The suite of pheromones that promote communal oviposition by Simulium vittatum, a North American black fly species, was identified and characterized using gas chromatography-mass spectrometry, electrophysiological, and behavioral bioassays. Behavioral assays demonstrated that communal oviposition was induced by egg-derived compounds that were active at short range and whose effect was enhanced through direct contact. Three compounds (cis-9-tetradecen-1-ol, 1-pentadecene, and 1-tridecene) were identified in a non-polar solvent extract of freshly deposited S. vittatum eggs that were capable of inducing the oviposition response. Electroantennography demonstrated that two of these three compounds (1-pentadecene and 1-tridecene) actively stimulated antennal neurons. Identification of the oviposition pheromones of this family may be helpful in developing control measures for nuisance black flies and for medically-important species such as Simulium damnosum sensu lato.