Complete elimination of hostplant quinolizidine alkaloids by larvae of a polyphagous lycaenid butterfly,Callophrys rubi

Caterpillars of the lycaenid butterfly Callophrys rubi accept a variety of hostplants. When fed inflorescences or leaves of Genista tinctoria (a natural hostplant) or Lupinus polyphyllus (a non-host), the larvae completely eliminate quinolizidine alkaloids ingested from their food in their frass. No alkaloids are stored. Infestation by the parasitoid wasp Distatrix sancus (Braconidae) did not affect alkaloid elimination. The presence of an effective anti-toxin system is discussed with reference to the evolution of hostplant relationships in the genus Callophrys. There is no evidence that in the secondarily myrmecoxenous larvae of C. rubi hostplantderived chemical defense takes the place of former myrmecophily.     

New Ecuadorian records of the eyeless banjo catfish Micromyzon akamai (Siluriformes: Aspredinidae) expand the species range and reveal intraspecific morphological variation

Two specimens of Micromyzon akamai, an eyeless and miniaturized species previously known only from the deep channels of the eastern Amazon basin in Brazil, are reported from the Curaray River, a tributary of the Napo River in Ecuador. The new specimens are the first records of Micromyzon in the headwaters of the Amazon River and the first records of M. akamai outside Brazil. External morphological characters and a phylogenetic analysis of cytochrome c oxidase I (coI) gene support the identification of the new specimens as M. akamai. Nevertheless, the new specimens also indicate that some features previously hypothesized to be apomorphic for M. akamai are intraspecifically variable.     

Stimulation of Bovicin HC5 Production and Selection of Improved Bacteriocin-Producing Streptococcus equinus HC5 Variants

Probiotics and Antimicrobial Proteins - Bovicin HC5 is a peptide that has inhibitory activity against various pathogenic microorganisms and food spoilage bacteria. Aiming to improve the...     

ReviewPart of the Series: From Dietary Antioxidants to Regulators in Cellular Signalling and Gene ExpressionReview: When is an antioxidant not an antioxidant? A review of novel actions and reactions of vitamin C

Vitamin C (or ascorbic acid) is regarded as the most important water-soluble antioxidant in human plasma and mammalian cells which have mechanisms to recycle and accumulate it against a concentration gradient, suggesting that the vitamin might also have important intracellular functions. In this review we summarize evidence from human trials that have attempted an association between vitamin C supplementation and an effect on biomarkers of oxidative DNA damage. Most studies reviewed herein showed either a vitamin C-mediated reduction in oxidative DNA damage or a null effect, whereas only a few studies showed an increase in specific base lesions. We also address the possible beneficial effects of vitamin C supplementation for the prevention of cancer and cardiovascular disease. Finally, we discuss the contribution of cell culture studies to our understanding of the mode of action of vitamin C and we review recent evidence that vitamin C is able to modulate gene expression and cellular function, with a particular interest in cell differentiation.     

Effects of aluminum on the energetic substrates in neotropical freshwater Astyanax bimaculatus (Teleostei: Characidae) females

We investigated the effects of acidic pH and acute aluminum (Al) exposure on the metabolic substrates of Astyanax bimaculatus, and on the ability of these animals to recover in clean water. After an acclimation period, sexually mature A. bimaculatus females were sorted into six glass aquaria with three experimental groups: control in neutral pH (7.0), acidic pH (5.5), and Al (0.5 mg·L^− 1) in acidic pH (5.5). After a 96 h treatment, 10 animals from each experimental group were sampled and the rest were returned to clean water in neutral pH without Al for a recovery period of 96 h. The acidic pH, either alone or combined with Al, decreased T4 levels, whereas Al exposure increased T3 levels. Recovery of T3 levels occurred after 96 h. Al exposure decreased ovary and plasma proteins, muscle glycogen contents, and hepatic lipids due to lipoperoxidation. In the recovery phase, lipids decreased in most tissues, probably to re-establish ovary protein and hepatic glycogen. A. bimaculatus prioritized the use of energetic resources during acclimatization to Al instead of prioritizing reproduction, thereby avoiding the ovulation of impaired eggs.     

Genotoxicity of Nicotiana tabacum leaves on Helix aspersa

Tobacco farmers are routinely exposed to complex mixtures of inorganic and organic chemicals present in tobacco leaves. In this study, we examined the genotoxicity of tobacco leaves in the snail Helix aspersa as a measure of the risk to human health. DNA damage was evaluated using the micronucleus test and the Comet assay and the concentration of cytochrome P450 enzymes was estimated. Two groups of snails were studied: one fed on tobacco leaves and one fed on lettuce (Lactuca sativa L) leaves (control group). All of the snails received leaves (tobacco and lettuce leaves were the only food provided) and water ad libitum. Hemolymph cells were collected after 0, 24, 48 and 72 h. The Comet assay and micronucleus test showed that exposure to tobacco leaves for different periods of time caused significant DNA damage. Inhibition of cytochrome P450 enzymes occurred only in the tobacco group. Chemical analysis indicated the presence of the alkaloid nicotine, coumarins, saponins, flavonoids and various metals. These results show that tobacco leaves are genotoxic in H. aspersa and inhibit cytochrome P450 activity, probably through the action of the complex chemical mixture present in the plant.     

Trans mechanism for ubiquitin-like protein transfer in autophagy

Comment on: Taherbhoy AM, et al. Mol Cell 2011; 44:451–61     

Antioxidant therapy: Still in search of the ‘magic bullet’

The therapeutic potential of natural phenolic antioxidants in human diseases associated with oxidative damage has received great attention to date. Appraisal of literature evidences that, in general, antioxidant therapy has enjoyed relative successes in preclinical studies but little benefits in human intervention studies or clinical trials. In fact, despite the huge, largely untapped potential therapeutic benefit of natural phenolic antioxidants, such as vitamins, non-flavonoid and flavonoid compounds, they appear not to be suitable drug candidates. The problem may be related, among others, to their non-drug-likeness properties. Though controversial the results obtained so far confirm the importance of exploring phenolic natural systems as safe templates for the design of new antioxidants. To support the assumption an outlook of the lead structural optimization process to improve ADME properties was given by means of natural hydroxycinnamic acids as a case study. The optimization of drug physicochemical properties and the development of appropriate delivery antioxidant systems can provide in the next future a way out to attain effective therapeutic antioxidant agents.