143 research outputs found

    A semiochemical view of the ecology of the seed beetle Acanthoscelides obtectus Say (Coleoptera: Chrysomelidae, Bruchinae)

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    The dried bean beetle, Acanthoscelides obtectus, is an economically important pest of stored legumes worldwide. Tracking the human-aided dispersion of its primary hosts, the Phaseolus vulgaris beans, it is now widespread in most bean-growing areas of the tropics and subtropics. In temperate regions where it can only occasionally overwinter in the field, A. obtectus proliferates in granaries, having multiple generations a year. Despite its negative impact on food production, no sensitive detection or monitoring tools exist, and the reduction of local populations still relies primarily on inorganic insecticides as fumigating agents. However, in the quest to produce more nutritious food more sustainably and healthily, the development of environmentally benign crop protection methods is vital against A. obtectus. For this, knowledge of the biology and chemistry of both the host plant and its herbivore will underpin the development of, among others, chemical ecology-based approaches to form an essential part of the toolkit of integrated bruchid management. We review the semiochemistry of the mate- and host-finding behaviour of A. obtectus and provide new information about the effect of seed chemistry on the sensory and behavioural ecology of host acceptance and larval development

    The common truncation variant in pancreatic lipase related protein 2 (PNLIPRP2) is expressed poorly and does not alter risk for chronic pancreatitis

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    A nonsense variant (p.W358X) of human pancreatic lipase related protein 2 (PNLIPRP2) is present in different ethnic populations with a high allele frequency. In cell culture experiments, the truncated protein mainly accumulates inside the cells and causes endoplasmic reticulum stress. Here, we tested the hypothesis that variant p.W358X might increase risk for chronic pancreatitis through acinar cell stress. We sequenced exon 11 of PNLIPRP2 in a cohort of 256 subjects with chronic pancreatitis (152 alcoholic and 104 non-alcoholic) and 200 controls of Hungarian origin. We observed no significant difference in the distribution of the truncation variant between patients and controls. We analyzed mRNA expression in human pancreatic cDNA samples and found the variant allele markedly reduced. We conclude that the p.W358X truncation variant of PNLIPRP2 is expressed poorly and has no significant effect on the risk of chronic pancreatitis

    Dissociating Variability and Effort as Determinants of Coordination

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    When coordinating movements, the nervous system often has to decide how to distribute work across a number of redundant effectors. Here, we show that humans solve this problem by trying to minimize both the variability of motor output and the effort involved. In previous studies that investigated the temporal shape of movements, these two selective pressures, despite having very different theoretical implications, could not be distinguished; because noise in the motor system increases with the motor commands, minimization of effort or variability leads to very similar predictions. When multiple effectors with different noise and effort characteristics have to be combined, however, these two cost terms can be dissociated. Here, we measure the importance of variability and effort in coordination by studying how humans share force production between two fingers. To capture variability, we identified the coefficient of variation of the index and little fingers. For effort, we used the sum of squared forces and the sum of squared forces normalized by the maximum strength of each effector. These terms were then used to predict the optimal force distribution for a task in which participants had to produce a target total force of 4–16 N, by pressing onto two isometric transducers using different combinations of fingers. By comparing the predicted distribution across fingers to the actual distribution chosen by participants, we were able to estimate the relative importance of variability and effort of 1∶7, with the unnormalized effort being most important. Our results indicate that the nervous system uses multi-effector redundancy to minimize both the variability of the produced output and effort, although effort costs clearly outweighed variability costs

    Palynomorphs of the Normapolles group and related plant mesofossils from the Iharkút vertebrate site, Bakony Mountains (Hungary)

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    Abstract Palynological and paleobotanical investigation of bonebeds and other strata of the Csehbánya Formation from the vertebrate locality at Iharkút (Bakony Mts, Hungary) reveals well-preserved Santonian palynological assemblages dominated by the Normapolles group, with a minor component consisting of other angiosperm pollen, some gymnosperm pollen, and spores. Eleven species of Normapolles-type pollen grains belonging to seven genera and fruit remains of a new taxon, Sphaeracostata barbackae gen. et sp. nov., are described. The new species is very abundant in the material, represented by ca. 1000 specimens. The genus Caryanthus Friis and an unnamed form previously reported from Haţeg by Lindfors et al. (2010) are also present. Plants producing Normapolles-type pollen grains diversified during the Late Cretaceous, with a bloom in the Santonian. The palynostratigraphy of the Upper Cretaceous terrestrial sediments in the studied region is based on Normapolles-related species. The studied assemblage is assigned to the Oculopollis zaklinskaiae-Tetracolporopollenites (Brecolpites) globosus Zone (or Zone C) indicating a late Santonian age. Comparison of the Iharkút palynoflora with other known Upper Cretaceous palynofloras of Central Europe shows diachronous occurrence of Normapolles taxa at different geographic localities and warrants further investigation. The ecological requirements of the amphibian fauna reflect azonal conditions controlled by the availability of water, which is in agreement with the inferred ecological conditions based on the paleobotanical investigations. The fauna is of entirely non-marine character, further supported by isotope studies, in line with our data showing that the palynological samples contain no marine forms

    Evidence for diagnosis of early chronic pancreatitis after three episodes of acute pancreatitis : a cross-sectional multicentre international study with experimental animal model

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    Chronic pancreatitis (CP) is an end-stage disease with no specific therapy; therefore, an early diagnosis is of crucial importance. In this study, data from 1315 and 318 patients were analysed from acute pancreatitis (AP) and CP registries, respectively. The population from the AP registry was divided into AP (n=983), recurrent AP (RAP, n=270) and CP (n=62) groups. The prevalence of CP in combination with AP, RAP2, RAP3, RAP4 and RAP5+was 0%, 1%, 16%, 50% and 47%, respectively, suggesting that three or more episodes of AP is a strong risk factor for CP. Laboratory, imaging and clinical biomarkers highlighted that patients with RAP3+do not show a significant difference between RAPs and CP. Data from CP registries showed 98% of patients had at least one AP and the average number of episodes was four. We mimicked the human RAPs in a mouse model and found that three or more episodes of AP cause early chronic-like morphological changes in the pancreas. We concluded that three or more attacks of AP with no morphological changes to the pancreas could be considered as early CP (ECP).The new diagnostic criteria for ECP allow the majority of CP patients to be diagnosed earlier. They can be used in hospitals with no additional costs in healthcare.Peer reviewe

    Multimodal Stimulation of Colorado Potato Beetle Reveals Modulation of Pheromone Response by Yellow Light

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    Orientation of insects to host plants and conspecifics is the result of detection and integration of chemical and physical cues present in the environment. Sensory organs have evolved to be sensitive to important signals, providing neural input for higher order multimodal processing and behavioral output. Here we report experiments to determine decisions made by Colorado potato beetle (CPB), Leptinotarsa decemlineata, in response to isolated stimuli and multimodal combinations of signals on a locomotion compensator. Our results show that in complete darkness and in the absence of other stimuli, pheromonal stimulation increases attraction behavior of CPB as measured in oriented displacement and walking speed. However, orientation to the pheromone is abolished when presented with the alternative stimulation of a low intensity yellow light in a dark environment. The ability of the pheromone to stimulate these diurnal beetles in the dark in the absence of other stimuli is an unexpected but interesting observation. The predominance of the phototactic response over that to pheromone when low intensity lights were offered as choices seems to confirm the diurnal nature of the insect. The biological significance of the response to pheromone in the dark is unclear. The phototactic response will play a key role in elucidating multimodal stimulation in the host-finding process of CPB, and perhaps other insects. Such information might be exploited in the design of applications to attract and trap CPB for survey or control purposes and other insect pests using similar orientation mechanisms
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