European checkerspots (Melitaeini: Lepidoptera,Nymphalidae) are not aposematic – the point of view of great tits (Parus major)

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Assessment of establishment and persistence of entomopathogenic nematodes for biological control of western corn rootworm

Abstract:  The use of entomopathogenic nematodes (EPN) is potentially one ecological approach to control the invasive alien western corn rootworm ( Diabrotica virgifera virgifera LeConte, Col., Chrysomelidae) in Europe. This study investigated the establishment and the short- and long-term persistence of Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), Heterorhabditis megidis Poinar, Jackson and Klein (Rh., Heterorhabditidae) and Steinernema feltiae Filipjev (Rh., Steinernematidae) in three maize fields in southern Hungary, using the insect-baiting technique. All three EPN species equally established and persisted in maize fields. The timing of application (April or June) did not influence the establishment of EPN species. EPNs persisted for 2–5 months, i.e. they survived up to and throughout D. v. virgifera larval occurrence in the soil. Results demonstrate that D. v. virgifera larvae can potentially be controlled by EPNs during the same year of EPN application but no long-term control effect is expected under intensive maize cultivation practices.     

DNA barcoding of South Africa’s ornamental freshwater fish – are the names reliable?

Trade in freshwater ornamental fish in South Africa is currently regulated by a ‘blacklist’ to prevent potentially invasive taxa from establishing in the country. Because its effective implementation requires accurate identification, the aim of the present study was to test whether DNA barcoding is a useful tool to identify freshwater fishes in the South African pet trade. A total of 351 aquarium fish specimens, representing 185 traded taxa, were sequenced for the mitochondrial COI barcoding marker in 2011 and 2012. Lake Malawi cichlids were treated as a single group due to a lack of resolution in their COI marker, resulting in a data set of 137 successfully sequenced taxa. The Barcode Of Life Database (BOLD) and GenBank were used for taxonomic assignment comparisons. The genetic identification matched the scientific name inferred from the trade name for 60 taxa (43.8%) using BOLD, and for 67 taxa (48.9%) using GenBank. A genetic ID could not be assigned in 47 (34.3%) cases using BOLD and in 37 cases (27%) using GenBank. Whereas DNA barcoding can be a useful tool to help identify imported freshwater fishes, it requires further development of publicly available databases to become a reliable means of identification.     

The high potential iron-sulfur cluster of aconitase is a binuclear iron-sulfur cluster.

It has been reported (Ruzicka, F.J., and Beinert, H. (1978) J. Biol. Chem. 253, 2514-2517) that aconitase in the oxidized state, as isolated, shows an electron paramagnetic resonance signal centered at g = 2.01, typical of high potential iron-sulfur proteins. Since the magnetic state corresponding to this signal has thus far only been found in tetranuclear iron-sulfur clusters in model compounds and proteins, it could be expected that aconitase also contains a [4Fe-4S] cluster. We show here that core extrusion, in the presence of hexamethylphosphoramide and o-xylyl-alpha,alpha'-dithiol and subsequent ligand exchange with p-trifluoromethylbenzenethiol yield absorption spectra typical of binuclear iron-sulfur clusters. According to the absorbance measured, the concentration of the extruded [2Fe-2S] cluster quantitatively accounts for the iron-sulfur content of the preparations examined. Preliminary studies of the 19F nuclear magnetic resonance spectrum obtained on extrusion with p-trifluoromethylbenzenethiol confirm the presence of a binuclear cluster in aconitase.     

Screening for Vulnerability in Older Cancer Patients: The ONCODAGE Prospective Multicenter Cohort Study

Background

Geriatric Assessment is an appropriate method for identifying older cancer patients at risk of life-threatening events during therapy. Yet, it is underused in practice, mainly because it is time- and resource-consuming. This study aims to identify the best screening tool to identify older cancer patients requiring geriatric assessment by comparing the performance of two short assessment tools the G8 and the Vulnerable Elders Survey (VES-13).

Patients and Methods

The diagnostic accuracy of the G8 and the (VES-13) were evaluated in a prospective cohort study of 1674 cancer patients accrued before treatment in 23 health care facilities. 1435 were eligible and evaluable. Outcome measures were multidimensional geriatric assessment (MGA), sensitivity (primary), specificity, negative and positive predictive values and likelihood ratios of the G8 and VES-13, and predictive factors of 1-year survival rate.

Results

Patient median age was 78.2 years (70-98) with a majority of females (69.8%), various types of cancer including 53.9% breast, and 75.8% Performance Status 0-1. Impaired MGA, G8, and VES-13 were 80.2%, 68.4%, and 60.2%, respectively. Mean time to complete G8 or VES-13 was about five minutes. Reproducibility of the two questionnaires was good. G8 appeared more sensitive (76.5% versus 68.7%, P =  0.0046) whereas VES-13 was more specific (74.3% versus 64.4%, P<0.0001). Abnormal G8 score (HR = 2.72), advanced stage (HR = 3.30), male sex (HR = 2.69) and poor Performance Status (HR = 3.28) were independent prognostic factors of 1-year survival.

Conclusion

With good sensitivity and independent prognostic value on 1-year survival, the G8 questionnaire is currently one of the best screening tools available to identify older cancer patients requiring geriatric assessment, and we believe it should be implemented broadly in daily practice. Continuous research efforts should be pursued to refine the selection process of older cancer patients before potentially life-threatening therapy.     

Geranylgeranyltransferase I of Candida albicans: null mutants or enzyme inhibitors produce unexpected phenotypes

Geranylgeranyltransferase I (GGTase I) catalyzes the transfer of a prenyl group from geranylgeranyl diphosphate to the carboxy-terminal cysteine of proteins with a motif referred to as a CaaX box (C, cysteine; a, usually aliphatic amino acid; X, usually L). The alpha and beta subunits of GGTase I from Saccharomyces cerevisiae are encoded by RAM2 and CDC43, respectively, and each is essential for viability. We are evaluating GGTase I as a potential target for antimycotic therapy of the related yeast, Candida albicans, which is the major human pathogen for disseminated fungal infections. Recently we cloned CaCDC43, the C. albicans homolog of S. cerevisiae CDC43. To study its role in C. albicans, both alleles were sequentially disrupted in strain CAI4. Null Cacdc43 mutants were viable despite the lack of detectable GGTase I activity but were morphologically abnormal. The subcellular distribution of two GGTase I substrates, Rho1p and Cdc42p, was shifted from the membranous fraction to the cytosolic fraction in the cdc43 mutants, and levels of these two proteins were elevated compared to those in the parent strain. Two compounds that are potent GGTase I inhibitors in vitro but that have poor antifungal activity, J-109,390 and L-269,289, caused similar changes in the distribution and quantity of the substrate. The lethality of an S. cerevisiae cdc43 mutant can be suppressed by simultaneous overexpression of RHO1 and CDC42 on high-copy-number plasmids (Y. Ohya et al., Mol. Biol. Cell 4:1017, 1991; C. A. Trueblood, Y. Ohya, and J. Rine, Mol. Cell. Biol. 13:4260, 1993). Prenylation presumably occurs by farnesyltransferase (FTase). We hypothesize that Cdc42p and Rho1p of C. albicans can be prenylated by FTase when GGTase I is absent or limiting and that elevation of these two substrates enables them to compete with FTase substrates for prenylation and thus allows sustained growth.     

Reaction of Desulfovibrio vulgaris two-iron superoxide reductase with superoxide: insights from stopped-flow spectrophotometry

Stopped-flow mixing of the Desulfovibrio vulgaris two-iron superoxide reductase (2Fe-SOR) containing the ferrous active site with superoxide generates a dead time intermediate whose absorption spectrum is identical to that of a putative ferric-hydroperoxo intermediate previously observed by pulse radiolysis. The dead time intermediate is shown to be a product of reaction with superoxide and to be generated at a much higher proportion of active sites than by pulse radiolysis. This intermediate decays smoothly to the resting ferric active site ( approximately 30 s-1 at 2 degrees C and pH 7) with no other detectable intermediates. Deuterium isotope effects demonstrate that solvent proton donation occurs in the rate-determining step of dead time intermediate decay and that neither of the conserved pocket residues, Glu47 or Lys48, functions as a rate-determining proton donor between pH 6 and pH 8. Fluoride, formate, azide, and phosphate accelerate decay of the dead time intermediate and for azide or fluoride lead directly to ferric-azido or -fluoro complexes of the active site, which inhibit Glu47 ligation. A solvent deuterium isotope effect is observed for the azide-accelerated decay, and the decay rate constants are proportional to the concentrations and pKa values of HX (X- = F-, HCO2-, N3-). These data indicate that the protonated forms of the anions function analogously to solvent as general acids in the rate-determining step. The results support the notion that the ferrous SOR site reacts with superoxide by an inner sphere process, leading directly to the ferric-hydroperoxo intermediate, and demonstrate that the decay of this intermediate is subject to both specific- and general-acid catalysis.     

What a tangled web we weave: discriminating between malingering and anosmia

Two groups of normosmic subjects were instructed to feign a total olfactory loss when tested with the Olfactory Confusion Matrix (OCM). One of the groups was given specific instructions as to the number of odorants and trials in the test, as well as the number of items that might be expected to be correctly identified by chance. The responses of both groups of malingerers were compared with responses gathered from a group of anosmic patients. The groups did not differ in terms of performance level (percent correct). In spite of the similarity in terms of accuracy level, an analysis of the pattern of OCM responses to an irritant allowed the anosmic patients to be distinguished from subjects attempting to feign a loss. Subjects were given explicit details about the test performed at the same level as those simply told to feign a loss. These results suggest that the OCM is an effective tool in separating malingering from anosmia.