Differentiation of embryonic stem cells to insulin-secreting structures similar to pancreatic islets

Although the source of embryonic stem (ES) cells presents ethical concerns, their use may lead to many clinical benefits if differentiated cell types can be derived from them and used to assemble functional organs. In pancreas, insulin is produced and secreted by specialized structures, islets of Langerhans. Diabetes, which affects 16 million people in the United States, results from abnormal function of pancreatic islets. We have generated cells expressing insulin and other pancreatic endocrine hormones from mouse ES cells. The cells self-assemble to form three-dimensional clusters similar in topology to normal pancreatic islets where pancreatic cell types are in close association with neurons. Glucose triggers insulin release from these cell clusters by mechanisms similar to those employed in vivo. When injected into diabetic mice, the insulin-producing cells undergo rapid vascularization and maintain a clustered, islet-like organization.     

Sesquiterpene lactones with potential use as natural herbicide models. 2. guaianolides

A structure-activity study to evaluate the effect of 17 guaianolide sesquiterpene lactones (in a range of 100-0.001 microM) on the growth and germination of several mono- and dicotyledon target species is accomplished. Results are compared with those obtained in the same bioassay with an internal standard, the commercial herbicide Logran, to validate the results with a known active formulation and to compare the results with a commercial product to test their potential use as natural herbicide models. Specific conditions for the selective mono- or polyhydroxylation of guaianolides using the SeO(2)/tert-butyl hydroperoxide system are presented and discussed. The high regio- and stereoselectivities of the reaction are explained through the specific structural requirements of the bulky first adduct formed during the ene reaction. These compounds appear to have deeper effects on the growth of either monocots or dicots than the previously tested germacranolides. Otherwise, the lactone group seems to be necessary for the activity, though it does not necessarily need to be unsaturated. However, the presence of a second and easily accessible unsaturated carbonyl system greatly enhances the inhibitory activity. Lipophilicity and the stereochemistry of the possible anchoring sites are also crucial factors for the activity. Finally, the levels of growth inhibition obtained with some compounds on dicots or monocots are totally comparable to those of Logran and allow proposing them as lead compounds.     

Quantitation of short-chain glycerol-bound compounds in thermoxidized and used frying oils. A monitoring study during thermoxidation of olive and sunflower oils

Major short-chain glycerol-bound compounds were investigated in olive oil (OO) and conventional sunflower oil (SO) during thermoxidation at 180 degrees C for 5, 10, and 15 h. These compounds included methyl heptanoate (C7:0), methyl octanoate (C8:0), methyl 8-oxo-octanoate (8-oxo-C8:0), methyl 9-oxononanoate (9-oxo-C9:0), dimethyl octanodiate (C8:0 diester), and dimethyl nonanodiate (C9:0 diester), which were analyzed by GC after derivatization of triacylglycerols to fatty acid methyl esters. An acceptable linear correlation (r = 0.967) was found between the total content of these compounds and the total content of polar compounds, suggesting that quantitation of the major short-chain glycerol-bound compounds provides a good indication of the total alteration level of oils heated at frying temperature. Samples with levels of polar compounds around 25% on oil showed total contents within 2-3 mg/g of oil. To determine the content of these compounds in used frying oils, 10 samples from restaurants and fried-food outlets in Spain were analyzed. Results showed total levels between 2.13 and 7.56 mg/g of oil in samples with contents of polar compounds ranging from 18.8 to 55.5% on oil. Samples with levels of polar compounds of approximately 25% showed total contents of the short-chain compounds similar to those found in the thermoxidized oils, that is, within 2-3 mg/g of oil.     

Selection for contrasting tocopherol content and profile in Ethiopian mustard

Tocopherols are compounds present in oilseeds with major effect on nutritional and technological properties of seed oils. Brassica spp. mainly contain varying concentrations of α‐tocopherol, with high vitamin E value, and γ‐tocopherol, which contributes to oil stability. The objective of this research was to select for contrasting tocopherol content and profile in Ethiopian mustard (Brassica carinata A. Braun). A collection of 211 F_4:5 lines was evaluated for tocopherol content and profile, and divergent selection was conducted till the S_3:4 generation. Selection resulted in two lines with increased tocopherol content (244 and 243 mg/kg seed as average of four environments), one line with reduced tocopherol content (117 mg/kg), two lines with reduced α/γ‐tocopherol ratio (0.22 and 0.28) and two lines with increased α/γ‐tocopherol ratio (3.74 and 3.34). Control line C‐101 averaged 196 mg/kg with α/γ‐tocopherol ratio of 1.10. Reduced α/γ‐tocopherol ratio was controlled by recessive alleles at a single locus. Seed to plant correlation was high (r = 0.92), which suggests the feasibility of selecting at the single‐seed level.     

Intraspecific breeding for reduced glucosinolate content in Ethiopian mustard (Brassica carinata A. Braun)

A total of six Ethiopian mustard ( Brassica carinata A. Braun) lines showing reduced levels of total glucosinolate content were developed through two different approaches. In the first case, eight lines with good agronomic performance under southern-Spanish conditions were first evaluated during two years for glucosinolate content, and a pedigree selection was then performed during three further generations. The line N2-142, with an average glucosinolate content of 82 μmoles g-1 seed, was developed from the original line C-49, with an average glucosinolate content of 115 μmoles g-1 seed. In the second case, chemical mutagenesis (EMS 1% v/v) was applied to seeds from the line C- 101, with an average glucosinolate content of 125 μmoles g- 1 seed. Five mutant lines showing an average glucosinolate content between 20 and 30 μmoles g-1 seed lower than the wild line C-101 were isolated in the M_3 or M_4 generation. The reduced glucosinolate content of these mutants was confirmed by developing and analysing the M_5 generation. Previous results in B. juncea suggest that a further reduction of total glucosinolate content might be achieved through genetic recombination between the different lines developed in this work. This revised version was published online in July 2006 with corrections to the Cover Date.     

Sesquiterpene lactones with potential use as natural herbicide models (I): trans,trans-germacranolides.

A structure-activity study to evaluate the effect of the trans, trans-germacranolide sesquiterpene lactones costunolide, parthenolide, and their 1,10-epoxy and 11,13-dihydro derivatives (in a range of 100-0.001 microM) on the growth and germination of several mono and dicotyledon target species is accomplished. Results are compared with those obtained in the same bioassay with an internal standard, the commercial herbicide Logran, to validate the results with a known active formulation and to compare the results with a commercial product to test their potential use as natural herbicide models. These compounds appear to have a more selective effects on the radicle growth of monocotyledons. Certain factors such as the presence of nucleophile-acceptor groups and their accessibility enhance the inhibitory activity. The levels of radicle inhibition obtained with some compounds on wheat are totally comparable to those of Logran and allow to propose them as lead compounds.     

Effect of the density on the growth and survival of the Caribbean scallops Argopecten nucleus and Nodipecten nodosus in suspended culture

Juveniles of the Caribbean scallops Argopecten nucleus and Nodipecten nodosus were suspended in pearl nets at densities of 25%, 30% and 50% coverage of the bottom of the net (BC) during days. Additionally, adults of A. nucleus (>35 mm) were placed in lantern nets at densities of 40%, 50% and 65% BC during days. Stocking density affected the growth of animals, with higher growth rates obtained at the lower densities. Although the survival of the two scallops was not influenced at the densities studied, the 15-day net changes, and culture in water of <28 °C produced better survival of A. nucleus and N. nodosus respectively. Predators of the families Cymatiidae, Grapsidae, Portunidae, Majidae and Xanthidae were found in the culture nets of juvenile A. nucleus , but during the adult phase they were absent. Predators exhibited a dense-independent behaviour in relation to scallops. There was not any association between predator frequency and survival of A. nucleus .     

Marine and freshwater crab meals in diets for red porgy (Pagrus pagrus): effect on growth,fish composition and skin colour

River crab (RC) meal (Procambarus clarkii) and marine crab (MC) meal (Chaceon affinis) were tested as a partial replacement for fish meal in diets for red porgy (Pagrus pagrus), and their effects on growth performance, fish proximate composition and skin colouration were evaluated. Red porgy were fed during 165 days with five diets. High‐quality fish meal diet was used as a control diet (CD). Protein of fish meal in the control was replaced by increasing the dietary levels of protein derived from RC and MC by up to 10% and 20% of each of them (RC10, RC20, MC10 and MC20). Fish fed on MC20 showed the highest values in feed intake, weight gain and growth (%). No differences were found in FCR and protein efficiency ratio among the treatments. Inclusion of both crab meals in diets significantly decreased the lipid content in whole fish compared with the control animals. On the other hand, no differences in muscle composition were found between the diets. Feeding both crab meals resulted in colour improvement compared with that of the control fish, with better hue values for the RC meal group than those for the MC meal group. The crab meals tested in the present study are suitable as a partial replacement for fish meal in diets for the red porgy, with the MC meal improving growth and both crabs meals improving skin colour, with further improvements in skin colour produced in fish‐fed diets containing the RC meal.     

Balancing resource protection and fishing activity: The case of the European hake in the northern Iberian Peninsula

One of the fundamental aims of the Ecosystem Approach to Fisheries Management is to ensure the long‐term sustainability of the fishery by protecting key life‐cycle habitats, such as recruitment areas. In this study, we apply a hurdle Bayesian hierarchical spatio‐temporal model that describes the abundance of European hake (Merluccius merluccius) recruits in the northern continental shelf of the Iberian Peninsula. Our findings clearly show four persistent nurseries, the main one being located along the continental shelf of the Artabrian gulf (off La Coruña). The preferential habitats identified for the hake recruits are areas within a bathymetric range of 120–200 m, with 15–16°C of Sea Surface Temperature, a Chl‐a concentration of 0.8–1.2 mg/m³ and low values of seabed rugosity (unconsolidated substrates). Searching for a compromise with fisheries, we also assess the degree of overlap of the main nursery areas with two fisheries footprints, a local one using Vessel Monitoring System data of trawl fishery of Marín, and a global one using Automatic Identification System data of different type of trawlers (bottom otter, beam and midwater trawls). The two fisheries footprints present different degree of overlapping in distinct areas, highlight the need of specific fleet‐adapted management rules in order to protect juvenile stages. We discuss that understanding the distributional patterns associated with key life stages, such as recruitment, and their interaction with fishing activities, is essential for applying appropriate spatial management measures and improving fishery sustainability.