Insect antifeedant activity of clerodane diterpenes and related model compounds

A comprehensive compilation of all test results on the insect antifeedant activity of clerodane diterpenes and related model compounds is reported. To increase the compatibility of data from different sources, some of the results reported in the literature have been converted into a standardized form. The compounds were sorted into groups according to the different types of sidechain attached to C-9. Despite the wealth of information, collected in 15 tables, it remains difficult to assign importance to separate structural elements in relation to the observed antifeedant activity. A detailed analysis of the structure-activity relationships could not be presented, but some interesting trends can be distinguished based on the structures of the strongest antifeedants. The compilation covers the literature up to December 2001.     

Vector competence of Australian Culex gelidus Theobald (Diptera: Culicidae) for endemic and exotic arboviruses

The recent recognition of established populations of the mosquito, Culex gelidus Theobald, in Australia has raised concerns about local transmission of arboviruses. The vector competence of a mainland population of Cx. gelidus was investigated for two local alphaviruses, Ross River (RRV) and Barmah Forest (BFV) viruses, and three flaviviruses, Japanese encephalitis (JEV), Kunjin (KUNV) and Murray Valley encephalitis (MVEV) viruses. Colonised mosquitoes were exposed to virus via blood-soaked pledgets and transmission was tested using a capillary-tube method. The important Australian vectors, Aedes vigilax (Skuse) and Culex annulirostris Skuse, were used as internal controls for the alphaviruses and flaviviruses, respectively. Overall, Cx. gelidus was a more efficient vector of flaviviruses than alphaviruses. Culex gelidus was refractory to infection with BFV, and nearly 25% transmitted RRV, which was comparable to Ae. vigilax . Culex gelidus was susceptible to all three flaviviruses, with transmission rates of 96%, 95% and 41% for JEV, KUNV and MVEV, respectively. JEV transmission rates in Cx. annulirostris were unexpectedly low and this was possibly due to differences in susceptibility to JEV genotypes I and II. Considering the high susceptibility to the flaviviruses demonstrated here, and the natural infections with RRV and JEV that have been detected from northern Australian populations, the establishment of the exotic mosquito, Cx. gelidus , in Australia is potentially a significant public health concern.     

Effects of Food Availability on Space and Refuge Use by a Neotropical Scatterhoarding Rodent

Animals that rely on refuges for safety can theoretically increase their foraging area without simultaneously increasing predation risk and travel costs by using more refuges. The key prediction of this theory, a negative correlation between food abundance, home range size and the number of refuges used, has never been empirically tested. We determined how home range size and refuge use by the Central American agouti (Dasyprocta punctata) varied across a gradient of abundance of the agoutis' principal food source: seeds and fruits of the palm Astrocaryum standleyanum. We used both manual and automated radio telemetry to measure space use of 11 agoutis during 2 mo of the Astrocaryum fruiting season, and of another set of 10 agoutis during 6 mo in which the animals largely relied on cached Astrocaryum seeds. We found that agoutis living in areas of lower food density had larger home ranges, and that all individuals used multiple refuges. The number of refuges, however, was not correlated with home range size. Consequently, agoutis that had larger home ranges roamed farther from their refuges. These results suggest that agoutis increase their home range size in response to food scarcity at the cost of their safety.     

Anisotropic adaptive finite element method for modelling blood flow

In this study, we present an adaptive anisotropic finite element method (FEM) and demonstrate how computational efficiency can be increased when applying the method to the simulation of blood flow in the cardiovascular system. We use the SUPG formulation for the transient 3D incompressible Navier–Stokes equations which are discretised by linear finite elements for both the pressure and the velocity field.

Given the pulsatile nature of the flow in blood vessels we have pursued adaptivity based on the average flow over a cardiac cycle. Error indicators are derived to define an anisotropic mesh metric field. Mesh modification algorithms are used to anisotropically adapt the mesh according to the desired size field. We demonstrate the efficiency of the method by first applying it to pulsatile flow in a straight cylindrical vessel and then to a porcine aorta with a stenosis bypassed by a graft. We demonstrate that the use of an anisotropic adaptive FEM can result in an order of magnitude reduction in computing time with no loss of accuracy compared to analyses obtained with uniform meshes.     

Adhesive interactions between voice prosthetic yeast and bacteria on silicone rubber in the absence and presence of saliva

Biofilms on silicone rubber voice prostheses are the major cause for frequent failure and replacement of these devices. The presence of both bacterial strains and yeast has been suggested to be crucial for the development of voice prosthetic biofilms. Adhesive interactions between Candida albicans, Candida krusei, and Candida tropicalis with 14 bacterial strains, all isolated from explanted voice prostheses were investigated in a parallel plate flow chamber. Bacteria were first allowed to adhere to silicone rubber, after which the flow chamber was perfused with yeast, suspended either in saliva or buffer. Generally, when yeast were adhering from buffer and saliva, the presence of adhering bacteria suppressed adhesion of yeast. In saliva, Rothia dentocariosa and Staphylococcus aureus enhanced adhesion of yeast, especially of C. albicans. This study shows that bacterial adhesion mostly reduces subsequent adhesion of yeast, while only a few bacterial strains stimulate adhesion of yeast, provided salivary adhesion mediators are present. Interestingly, different clinical studies have identified R. dentocariosa and S. aureus in biofilms on explanted prostheses of patients needing most frequent replacement, while C. albicans is one of the yeast generally held responsible for silicone rubber deterioration.     

Consumption Simulations Induce Salivation to Food Cues

Salivation to food cues is typically explained in terms of mere stimulus-response links. However, food cues seem to especially increase salivation when food is attractive, suggesting a more complex psychological process. Adopting a grounded cognition perspective, we suggest that perceiving a food triggers simulations of consuming it, especially when attractive. These simulations then induce salivation, which effectively prepares the body for eating the food. In two experiments, we systematically examined the role of simulations on salivation to food cues. As stimuli, both experiments used an attractive, a neutral, and a sour food, as well as a non-food control object. In Experiment 1, participants were instructed to simulate eating every object they would be exposed to. We then exposed them to each object separately. Salivation was assessed by having participants spit their saliva into a cup after one minute of exposure. In Experiment 2, we instructed half of participants to simulate eating each object, and half to merely look at them, while measuring salivation as in Experiment 1. Afterwards, participants rated their simulations and desire to eat for each object separately. As predicted, foods increased salivation compared to the non-food control object, especially when they were attractive or sour (Exp. 1 and 2). Importantly, attractive and sour foods especially increased salivation when instructed to simulate (Exp. 2). These findings suggest that consumption simulations play an important role in inducing salivary responses to food cues. We discuss directions for future research as well as the role of simulations for other appetitive processes.     

Synthesis and biological evaluation of asymmetric gramicidin S analogues containing modified d-phenylalanine residues

The synthesis of new analogues of the cationic antimicrobial peptide gramicidin S, having a modified d-phenylalanine residue, their antibacterial properties against several Gram positive and negative strains, as well as their hemolytic activity is reported.     

The common Scandinavian human leucocyte antigen ancestral haplotype 62.1 as prognostic factor in patients with advanced malignant melanoma

Purpose  We have previously demonstrated an association of the human leukocyte antigen (HLA), HLA-A2 allele with ovarian and prostate cancer mortality as well as a segregation of the ancestral HLA haplotype (AHH) 62.1 [(A2) B15 Cw3 DRB1*04] in patients with stage III–IV serous ovarian cancer. The objective of the present study was to determine the role of the HLA phenotype on the prognosis in stage III–IV malignant melanoma patients. Patients and methods  A cohort of metastatic malignant melanoma patients (n = 91), in stage III (n = 26) or IV (n = 65) were analysed for HLA-A, -B, -Cw and -DRB1 types by PCR/sequence-specific primer method. The frequencies of HLA alleles in the patients were compared to that of healthy Swedish bone marrow donors. The effect of HLA types on prognosis was defined by Kaplan–Meier and Cox analysis. Results  The presence of the AHH 62.1 in clinical stage IV patients was significantly and independently associated with the worst survival rate recorded from the appearance of metastasis (HR = 2.14; CI = 1.02–4.4; P = 0.04). In contrast, the period from the primary diagnosis to metastasis was the longest in patients with this haplotype (HR = 0.40; CI = 0.17–0.90; P = 0.02). Conclusions  Melanoma patients in our cohort with 62.1 AHH which is associated with autoimmune diseases have an initial strong anti-tumour control with longer metastasis-free period. These patients have rapid progression after the appearance of metastasis, responding poorly to chemo- or/and immunotherapy. This apparently paradoxical clinical process could be due to the interplay between tumour clones escape and immune surveillance ending up with a rapid disease progression. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Identifying the basal angiosperm node in chloroplast genome phylogenies: sampling one's way out of the Felsenstein zone

While there has been strong support for Amborella and Nymphaeales (water lilies) as branching from basal-most nodes in the angiosperm phylogeny, this hypothesis has recently been challenged by phylogenetic analyses of 61 protein-coding genes extracted from the chloroplast genome sequences of Amborella, Nymphaea, and 12 other available land plant chloroplast genomes. These character-rich analyses placed the monocots, represented by three grasses (Poaceae), as sister to all other extant angiosperm lineages. We have extracted protein-coding regions from draft sequences for six additional chloroplast genomes to test whether this surprising result could be an artifact of long-branch attraction due to limited taxon sampling. The added taxa include three monocots (Acorus, Yucca, and Typha), a water lily (Nuphar), a ranunculid (Ranunculus), and a gymnosperm (Ginkgo). Phylogenetic analyses of the expanded DNA and protein data sets together with microstructural characters (indels) provided unambiguous support for Amborella and the Nymphaeales as branching from the basal-most nodes in the angiosperm phylogeny. However, their relative positions proved to be dependent on the method of analysis, with parsimony favoring Amborella as sister to all other angiosperms and maximum likelihood (ML) and neighbor-joining methods favoring an Amborella + Nymphaeales clade as sister. The ML phylogeny supported the later hypothesis, but the likelihood for the former hypothesis was not significantly different. Parametric bootstrap analysis, single-gene phylogenies, estimated divergence dates, and conflicting indel characters all help to illuminate the nature of the conflict in resolution of the most basal nodes in the angiosperm phylogeny. Molecular dating analyses provided median age estimates of 161 MYA for the most recent common ancestor (MRCA) of all extant angiosperms and 145 MYA for the MRCA of monocots, magnoliids, and eudicots. Whereas long sequences reduce variance in branch lengths and molecular dating estimates, the impact of improved taxon sampling on the rooting of the angiosperm phylogeny together with the results of parametric bootstrap analyses demonstrate how long-branch attraction might mislead genome-scale phylogenetic analyses.