Genome‐wide association study reveals novel players in defense hormone crosstalk in Arabidopsis

Jasmonic acid (JA) regulates plant defenses against necrotrophic pathogens and insect herbivores. Salicylic acid (SA) and abscisic acid (ABA) can antagonize JA‐regulated defenses, thereby modulating pathogen or insect resistance. We performed a genome‐wide association (GWA) study on natural genetic variation in Arabidopsis thaliana for the effect of SA and ABA on the JA pathway. We treated 349 Arabidopsis accessions with methyl JA (MeJA), or a combination of MeJA and either SA or ABA, after which expression of the JA‐responsive marker gene PLANT DEFENSIN1.2 (PDF1.2) was quantified as a readout for GWA analysis. Both hormones antagonized MeJA‐induced PDF1.2 in the majority of the accessions but with a large variation in magnitude. GWA mapping of the SA‐ and ABA‐affected PDF1.2 expression data revealed loci associated with crosstalk. GLYI4 (encoding a glyoxalase) and ARR11 (encoding an Arabidopsis response regulator involved in cytokinin signalling) were confirmed by T‐DNA insertion mutant analysis to affect SA–JA crosstalk and resistance against the necrotroph Botrytis cinerea. In addition, At1g16310 (encoding a cation efflux family protein) was confirmed to affect ABA–JA crosstalk and susceptibility to Mamestra brassicae herbivory. Collectively, this GWA study identified novel players in JA hormone crosstalk with potential roles in the regulation of pathogen or insect resistance.     

Stocking rate and organic waste type affect development of three Chrysomya species and Lucilia sericata (Diptera: Calliphoridae): Implications for bioconversion

Fly larvae can be used effectively to reduce various organic waste types and produce value-added products, including protein as an ingredient in livestock feeds and oil for biodiesel production. However, fly development on different waste types may cause differences in growth rate and the body composition, which can further be influenced by fly species and their stocking rate. This study explored the impact of different waste types (kitchen waste, abattoir waste and swine manure) and larval stocking rate on growth and body composition of four blowfly species, Chrysomya chloropyga (Wiedemann), Chrysomya megacephala (Fabricius), Chrysomya putoria (Wiedemann) and Lucilia sericata (Meigen). First-instar larvae (20, 50 or 100), less than 3 hr old, were placed on 100 g of each waste type. Pre-pupal mass at commencement of post-feeding larval dispersal, time to onset of dispersal, survival and nutrient reserves were determined for each species, stocking rate and waste type. Our results revealed that larvae fed kitchen and abattoir waste had significantly higher dry mass, crude protein and lipid content compared with those fed swine manure. Higher survival rate was observed with increasing larval stocking rate. We provide important information to guide the mass production of high-quality nutrient-rich larvae and recommend C. putoria, which is versatile and effective on a range of waste products, as well as high in protein and lipids. The implications for waste management are discussed.     

Preliminary results on sperm motility and testicular histology of two feral fish species, Oreochromis mossambicus and Clarias gariepinus, from a currently DDT-sprayed area, South Africa

The effects of DDT and its metabolites on the reproductive health of two fish species (Clarias gariepinus and Oreochromis mossambicus) were studied using the gonadosomatic index (GSI), gonadal histology and computer assisted sperm analysis (CASA). DDT and its metabolites, DDE and DDD are endocrine disrupting chemicals posing estrogenic and anti‐androgenic properties, which have detrimental effects on growth and reproduction. Although DDT was banned internationally, it is still used for Malaria vector control in areas of South Africa. Both species were sampled at a reference site, Albasini dam (AD), (outside the DDT‐sprayed area, <0.01 μg L^?1 of DDT) and at an exposed site, Xikundu weir (XW), in the same river ± 70 km within the DDT‐sprayed area, <0.01 μg L^?1 of DDT. Gill nets were used to acquire a sample size of 10 male fish per site for each species. Both testes were dissected out and the GSI calculated. Uncontaminated milt was collected and analyzed using a novel CASA system based on open source software for characterization of sperm motility parameters. Testis tissue sampled for histology was fixed in Bouins and processed according to standard methods. The sample size obtained at the reference site (AD) was O. mossambicus n = 6, C. gariepinus n = 9; and at the exposed site (XW) was O. mossambicus n = 10, C. gariepinus n = 3. The GSI results showed a lower value for O. mossambicus at XW (0.06) (n = 13) than AD (0.12) (n = 6); U = 16.0, P = 0.044. However the opposite was true for C. gariepinus. Exposure to various environmental toxicants can result in gonadal changes such as decreased GSI, morphological alterations or both. Histological assessment showed histopathological alterations to testes tissue including intersex (only in O. mossambicus) and detachment of basal membranes. The CASA results showed a decrease in parameters from the reference site (AD) to the exposed site (XW) for both species. The decrease in percent motility (% MOT) for O. mossambicus from the reference site (AD) (n = 6) to the exposed site (XW) (n = 13) was statistically significant; U = 13.0, P = 0.023. C. gariepinus from the exposed site (XW) was most affected in terms of percent motility (10.00%) and velocity (67.94 μm s^?1). Detailed assessment of the environmental effects of DDT in this area seems crucial before population impacts become evident.     

The cytotoxic,neurotoxic, apoptotic and antiproliferative activities of extracts of some marine algae on the MCF-7 cell line

We investigated the cytotoxic, neurotoxic, apoptotic and antiproliferative effects of extracts from Petalonia fascia, Jania longifurca and Halimeda tuna on the MCF-7 breast cancer cell line. J. longifurca extracts were more toxic than those of P. fascia and H. tuna. The algal extracts showed significant toxic effects at different dilutions. The toxic effects were due to increased oxidative stress and resulted in apoptosis. Algal toxicity may exert negative effects through the food chain or by direct interaction. Algal toxicity also has potential for cancer therapy. The toxic effects that we observed may be especially important for therapy for breast tumors.     

A Linnaeus NG TM interactive key to the Lithocolletinae of North-West Europe aimed at accelerating the accumulation of reliable biodiversity data (Lepidoptera,Gracillariidae)

We present an interactive key that is available online through any web browser without the need to install any additional software, making it an easily accessible tool for the larger public. The key can be found at http://identify.naturalis.nl/lithocolletinae. The key includes all 86 North-West European Lithocolletinae, a subfamily of smaller moths (“micro-moths”) that is commonly not treated in field guides. The user can input data on several external morphological character systems in addition to distribution, host plant and even characteristics of the larval feeding traces to reach an identification. We expect that this will enable more people to contribute with reliable observation data on this group of moths and alleviate the workload of taxonomic specialists, allowing them to focus on other new keys or taxonomic work.     

Allergic inflammation does not impact chemical-induced carcinogenesis in the lungs of mice

Background

Although the relationship between allergic inflammation and lung carcinogenesis is not clearly defined, several reports suggest an increased incidence of lung cancer in patients with asthma. We aimed at determining the functional impact of allergic inflammation on chemical carcinogenesis in the lungs of mice.

Methods

Balb/c mice received single-dose urethane (1 g/kg at day 0) and two-stage ovalbumin during tumor initiation (sensitization: days -14 and 0; challenge: daily at days 6-12), tumor progression (sensitization: days 70 and 84; challenge: daily at days 90-96), or chronically (sensitization: days -14 and 0; challenge: daily at days 6-12 and thrice weekly thereafter). In addition, interleukin (IL)-5 deficient and wild-type C57BL/6 mice received ten weekly urethane injections. All mice were sacrificed after four months. Primary end-points were number, size, and histology of lung tumors. Secondary end-points were inflammatory cells and mediators in the airspace compartment.

Results

Ovalbumin provoked acute allergic inflammation and chronic remodeling of murine airways, evident by airspace eosinophilia, IL-5 up-regulation, and airspace enlargement. Urethane resulted in formation of atypical alveolar hyperplasias, adenomas, and adenocarcinomas in mouse lungs. Ovalbumin-induced allergic inflammation during tumor initiation, progression, or continuously did not impact the number, size, or histologic distribution of urethane-induced pulmonary neoplastic lesions. In addition, genetic deficiency in IL-5 had no effect on urethane-induced lung tumorigenesis.

Conclusions

Allergic inflammation does not impact chemical-induced carcinogenesis of the airways. These findings suggest that not all types of airway inflammation influence lung carcinogenesis and cast doubt on the idea of a mechanistic link between asthma and lung cancer.     

Initial steps towards a production platform for DNA sequence analysis on the grid

Background  

Bioinformatics is confronted with a new data explosion due to the availability of high throughput DNA sequencers. Data storage and analysis becomes a problem on local servers, and therefore it is needed to switch to other IT infrastructures. Grid and workflow technology can help to handle the data more efficiently, as well as facilitate collaborations. However, interfaces to grids are often unfriendly to novice users.