Durum wheat by-products as natural sources of valuable nutrients

This review reports the use of wheat milling by-products for the extraction of high quality oil and vitamin E including our results on the exploitation of durum wheat bran as a valuable source of important healthful compounds. Wheat oil can be used as an ingredient in food, pharmaceutical or cosmetic preparations because it contains important bioactive compounds such as vitamin E, carotenoids and unsaturated fatty acids. Different methods are used for oil recovery from plant materials, such as solvent extraction, mechanical pressing or the eco-friendly supercritical carbon dioxide (SC-CO₂) extraction technology. By using SC-CO₂, we obtained an oil from durum wheat (Triticum durum Desf.) bran and optimized the extraction conditions to increase oil and vitamin E yields. Wheat bran, which is composed of pericarp, aleurone layer and germ, is discarded during the early stages of durum wheat milling processes to obtain a final product (semolina) that is stable over time. Maximum oil and vitamin E yields were obtained when a durum wheat bran matrix with particle size of ~30 mesh and a moisture content of 2.6 % was used. The optimal conditions for oil extraction were: 300–350 bar, 60–70 °C, and 4 l min^?1 gaseous CO₂ flow rate for 1 h. The chemical composition (vitamin E forms, carotenoids, quinones, lipids and fatty acids) of the SC-CO₂ extracted oil was analyzed and compared to that of the oil extracted by Soxhlet using hexane as solvent. The findings here reported highlight the importance of durum wheat bran as a rich source of valuable natural nutrients.     

Subterranean termites (Isoptera: Rhinotermitidae): Exploitation of equivalent food resources with different forms of placement

Abstract Coptotermes gestroi and Heterotermes tenuis have been described as important urban pests in Brazil. The establishment of control technologies using baits that consider the social behavior of termites requires a better knowledge of their foraging behavior. Thus, this study analyzed the feeding behavior of these species with three different forms of food placement: food on the surface of a substrate and food either partially or completely buried in the substrate. Experimental arenas were composed of a central chamber connected to three food chambers. Each central chamber contained 550 foragers of C. gestroi or 517 foragers of H. tenuis. Blocks of Pinus elliottii were placed in the different food chambers. After 28 days, the consumption of each wood block and the percentage of foraging individuals recruited for food chambers were verified in relation to the total survival rate obtained for each one of the 20 replicates. Results showed that completely buried food was most consumed for H. tenuis and presented a higher recruitment rate of workers and soldiers for both species. Although the consumption had non‐significant differences for C. gestroi, these termites exhibited a tendency to prefer completely buried food. In these conditions, it can be concluded that the forms of food placement used in the present research influenced the recruitment of individuals for both species. Data also suggests that when the foraging subterranean termites find food resources in the tunneling substrate, they tend to concentrate their efforts on it, a behavior regime that reduces exposure to external environment.     

Thermodynamic and spectroscopic investigation on the role of Met residues in Cu(II) binding to the non-octarepeat site of the human prion protein

Among the common features shared by neurodegenerative diseases there is the central role played by specific proteins or peptides which accumulate in neurons as insoluble plaques or tangles, containing abnormal amounts of redox-active metal ions, like copper and iron. In the case of transmissible spongiform encephalopathies (TSE), the involved protein is known as "prion protein" (PrP(C)) since "prions" (proteinaceous and infectious) are the agents which make TSE transmissible. It is widely accepted that PrP(C), in its wild-type form, can bind up to six Cu(II) ions, four of them in the so-called "octarepeat domain" and the others in the "fifth (non-octarepeat) binding-site". The latter domain contains two His residues, acting as anchoring sites for Cu(II) ions, and other potential binding residues, such as Lys and Met. While it is widely accepted that Lys residues do not take part in complex-formation, the role of methionines is still debated. In order to shed light on this issue, some peptides have been synthesized, either directly mimicking the sequence of the second half of the fifth binding site of human-PrP(C) (apo-form) or analogues where Met residues have been substituted by n-leucine. In addition, a series of short peptides, containing both His and Met residues in different relative positions, have been investigated, for the sake of comparison. Spectroscopic results, including NMR spectra of systems containing Ni(II) as a probe for the paramagnetic Cu(II) ion, agree on the exclusion of any direct interaction between the sulphur atom of Met residues and the Cu(II) ion already bound to His-imidazole side-chains. However, thermodynamic data show that Met-109 somewhat contributes to stability of complex species and this can be attributed to different electronic and steric effects.     

Rhodolith beds are major CaCO3 bio-factories in the tropical South West Atlantic

Rhodoliths are nodules of non-geniculate coralline algae that occur in shallow waters (<150 m depth) subjected to episodic disturbance. Rhodolith beds stand with kelp beds, seagrass meadows, and coralline algal reefs as one of the world's four largest macrophyte-dominated benthic communities. Geographic distribution of rhodolith beds is discontinuous, with large concentrations off Japan, Australia and the Gulf of California, as well as in the Mediterranean, North Atlantic, eastern Caribbean and Brazil. Although there are major gaps in terms of seabed habitat mapping, the largest rhodolith beds are purported to occur off Brazil, where these communities are recorded across a wide latitudinal range (2°N-27°S). To quantify their extent, we carried out an inter-reefal seabed habitat survey on the Abrolhos Shelf (16°50'-19°45'S) off eastern Brazil, and confirmed the most expansive and contiguous rhodolith bed in the world, covering about 20,900 km(2). Distribution, extent, composition and structure of this bed were assessed with side scan sonar, remotely operated vehicles, and SCUBA. The mean rate of CaCO(3) production was estimated from in situ growth assays at 1.07 kg m(-2) yr(-1), with a total production rate of 0.025 Gt yr(-1), comparable to those of the world's largest biogenic CaCO(3) deposits. These gigantic rhodolith beds, of areal extent equivalent to the Great Barrier Reef, Australia, are a critical, yet poorly understood component of the tropical South Atlantic Ocean. Based on the relatively high vulnerability of coralline algae to ocean acidification, these beds are likely to experience a profound restructuring in the coming decades.     

New Strategy for Identification of Novel cry-Type Genes from Bacillus thuringiensis Strains

We designed five degenerate primers for detection of novel cry genes from Bacillus thuringiensis strains. An efficient strategy was developed based on a two-step PCR approach with these primers in five pair combinations. In the first step, only one of the primer pairs is used in the PCR, which allows amplification of DNA fragments encoding protein regions that include consensus domains of representative proteins belonging to different Cry groups. A second PCR is performed by using the first-step amplification products as DNA templates and the set of five primer combinations. Cloning and sequencing of the last-step amplicons allow both the identification of known cry genes encoding Cry proteins covering a wide phylogenetic distance and the detection and characterization of cry-related sequences from novel B. thuringiensis isolates.     

Comparative genomics of Helicobacter pylori isolates recovered from ulcer disease patients in England

Background  

Genomic diversity of H. pylori from many different human populations is largely unknown. We compared genomes of 65 H. pylori strains from Nottingham, England. Molecular analysis was carried out to identify rearrangements within and outside the cag-pathogenicity-island (cag PAI) and DNA sequence divergence in candidate genes. Phylogenetic analysis was carried out based on various high-resolution genotyping techniques.     

Development of methods to evaluate susceptibility of soybean aphid to imidacloprid and thiamethoxam at lethal and sublethal concentrations

The soybean aphid, Aphis glycines Matsumura (Homoptera: Aphididae), is a recent introduction (2000) from Asia and has become a serious soybean [Glycine max (L.) Merr. (Fabaceae)] pest in North America. Seed treatments using the neonicotinoid insecticides, imidacloprid and thiamethoxam, have been suggested as a method of control, and the use of these insecticides is becoming widespread. As a consequence, there is increased potential to select for resistance to these compounds. In the case of soybean aphids, baseline susceptibility to neonicotinoid insecticides and standardized methods for bioassay are lacking. A bioassay technique that uses excised soybean leaves immersed in an insecticide solution was developed to determine systemic insecticidal activity at lethal and sublethal concentrations. Mortality and population growth inhibition were evaluated after 7 days. Life table parameters were calculated by exposing 1‐day‐old aphids to three concentrations of thiamethoxam. Aphid mortality and nymph production were recorded daily until the entire cohort collapsed. Soybean aphid age‐specific survivorship, fecundity, net reproductive rate, longevity, intrinsic rate of increase, discrete daily growth rate, and life expectancy were all significantly reduced at higher thiamethoxam concentrations. Soybean aphid response to both insecticides was similar, and both compounds were very toxic with LC₅₀s of 31.3 and 16.9 ng ml^?1 and EC₅₀s of 6.3 and 5.4 ng ml^?1 for imidacloprid and thiamethoxam, respectively. These results indicate that the methods developed in this study had negligible impact on the life table estimates measured and can be used to develop a baseline of susceptibility as a benchmark for subsequent resistance monitoring. Given the rapid and widespread adoption of this new insecticide class, vigilant monitoring for changes in susceptibility will be essential to its long‐term sustainability.     

How Small is too Small? Camera Trap Survey Areas and Density Estimates for Ocelots in the Bolivian Chaco

Studies on carnivores, which are generally difficult to observe directly because they are elusive and nocturnal, are carried out through indirect methods, e.g. , camera trapping and radiotracking. The first method has been used to estimate population densities of species that can be differentiated as individuals using unique pelage patterns. However, the use of capture–recapture methodology has raised doubts regarding the estimation of the sampling area around the camera traps, which is obtained using maximum distances traveled by individuals photographed at two or more different locations. In this paper, the results from camera traps are compared with a radiotracking study carried out simultaneously with ocelots ( Leopardus pardalis ) to confirm whether maximum distances observed in camera traps coincide with ranging patterns determined from radio telemetry, and in turn whether the sampling areas estimated from camera traps are appropriate for estimating density. Mean maximum distance moved was 2880 m according to camera trap records during a 60-d survey period while, with radiotracking, the maximum distance moved was 3176 m during the same period. The difference is not significant, and the sampling areas estimated with camera traps to assess ocelot density are reliable. However, if the area covered by cameras is reduced to less than three to four times average home range for the target species, then density estimates from camera trapping are exaggerated because of the reduced observed distances and the fact that multiple individuals can overlap in relatively small areas.     

Targeting the X-linked inhibitor of apoptosis protein through 4-substituted azabicyclo[5.3.0]alkane smac mimetics. Structure, activity, and recognition principles

The X-linked inhibitor of apoptosis protein (XIAP) is overexpressed in several malignant cells where it prevents apoptosis by binding to, and blocking, the activation of caspase-3, -7, and -9. Human XIAP (479 residues) is composed of three tandem-repeated baculoviral IAP repeat (BIR) domains (BIR1-3), and by a C-terminal RING domain. Smac-DIABLO [second mitochondria-derived activator of caspases (Smac)-direct IAP binding protein with low pI (DIABLO)], the natural antagonist of XIAP, binds through its N-terminal sequence AVPI to the same surface groove, in the BIR domains, that binds caspases. Synthetic compounds mimicking such tetrapeptide motif effectively block the interaction between IAP and active caspases, thus triggering apoptosis. Peptidomimetics based on an azabicyclo[x.y.0]alkane scaffolds, have been shown to bind the BIR3 domain of XIAP with micromolar to nanomolar affinities, thus presenting attractive features for drug lead optimization. Here we report a study on three newly synthesized Smac mimetics, which have been characterized in their complexes with XIAP BIR3 domain through X-ray crystallography and molecular modelling/docking simulations. Based on analysis of the crystal structures, we show that specific substitutions at the 4-position of the azabicyclo[5.3.0]alkane scaffold results in sizeable effects on the peptidomimetic-BIR3 domain affinity. By means of functional, biophysical and simulative approaches we also propose that the same Smac mimetics can bind XIAP BIR2 domain at a location structurally related to the BIR3 domain AVPI binding groove. Details of the XIAP-Smac mimetic recognition principles highlighted by this study are discussed in light of the drug-like profile of the three (potentially proapoptotic) compounds developed that show improved performance in ADMET (adsorption, distribution, metabolism, excretion and toxicity) tests.