Influence of lipid physical state on the in vitro digestibility of emulsified lipids

The objective of this study was to investigate the influence of the physical state of emulsified lipids on their in vitro digestibility by pancreatic lipase. A 10 wt % tripalmitin oil-in-water emulsion stabilized by sodium dodecyl sulfate (0.9 wt % SDS) was prepared at a temperature (>70 degrees C) above the melting point of the lipid phase (T(m) approximately 60 degrees C). A portion of this emulsion was cooled to a temperature (0 degrees C for 15 min) well below the crystallization temperature of the emulsified lipid (T(c) approximately 22 degrees C) and then warmed to 37 degrees C so as to have completely solid lipid particles. Another portion of the emulsion was directly cooled from 70 to 37 degrees C (which is above the T(c)) to have completely liquid (supercooled) lipid particles. Pancreatic lipase (8 mg/mL) and bile extract (5.0 mg/mL) were then added to each emulsion at 37 degrees C, and the evolution of the particle charge, particle size, appearance, and free fatty acid release were measured over a period of 2 h. It was found that the rate and extent of lipid digestion were higher in the emulsion containing liquid particles but that appreciable lipid digestion still occurred in the emulsion containing solid particles (i.e., >35% lipid digestion after 2 h). These results may have important consequences for controlling the digestion rate of lipids or for developing solid lipid particle delivery systems for lipophilic functional components.     

Complete quantification of group A and group B soyasaponins in soybeans

A combination of high-pressure extraction and preparative chromatography was used to purify the group A and group B soyasaponins from soy germ for use as analytical standards and for use in biological assays. A standardized sample preparation and extraction method was developed for the analysis of phytochemicals found in soy and processed soy products, which is reproducible in other laboratories. The extracts can be analyzed with standard liquid chromatography-mass spectrometry and high-performance liquid chromatography methods to identify and quantitate the group A and group B forms of the soy saponins, as well as the soy isoflavones. Complete saponin analysis of the extracts prepared from soy germ (hypocots), hulls, and cotyledons shows that a significant portion of the saponins is concentrated in the germ. The germ contains nearly all of the group A soyasaponins, while the group B soyasaponins are nearly equally distributed between the germ and the cotyledons. The hulls contain little of either isoflavones or saponins. Whole (full fat) soybeans grown on a tract in central Illinois in 2003 contain approximately 4-6% saponins on a weight basis, of which about one-fifth or less of the total saponin content are group A soyasaponins; the balance is group B soyasaponins.     

Lipid oxidation and amylopectin molecular weight changes occurring during storage of extruded starch samples

Using thermomechanical extrusion, waxy maize starch and 4% (w/w) lipid were formed into strips. The lipids used were free fatty acids (mostly linoleic) and antioxidant stripped sunflower oil (either previously oxidised or fresh, with and without copper ions). By altering their water content it was possible to store, at the same temperature, sample strips in the glassy and rubbery states. Lipid oxidation was monitored by determining hexanal in the headspace above all stored samples. The molecular weights of the amylopectin in the samples of extruded products (dissolved in dimethylsulfoxide, precipitated and redissolved using a pressure cell) were determined by asymmetric flow-field-flow fractionation, analytical ultracentrifugation and light scattering. The initial rate of hexanal generation was higher in samples stored in the glassy state compared with those in the rubbery state. Waxy maize and extruded samples, at the start of the storage period and after 42 days, were used to establish the molecular weight of the amylopectin. A significant fall (a decrease of 40%) in molecular weight was found on storage of samples containing sunflower oil and copper ions and those containing free fatty acids, irrespective of the method used for molecular weight determination.     

Activity of feline interferon-omega after ocular or oral administration in cats as indicated by Mx protein expression in conjunctival and white blood cells

OBJECTIVE: To assess the biological response to recombinant feline interferon-omega (rFeIFN-omega) following ocular or oral administration in cats via estimation of Mx protein expression in conjunctival cells (CCs) and WBCs. ANIMALS: 10 specific pathogen-free cats. PROCEDURES: In multiple single-dose drug experiments, each cat received various concentrations of rFeIFN-omega administered topically into both eyes (50 to 10,000 U/eye) and orally (200 to 20,000 units). The same cats received saline (0.9% NaCl) solution topically and orally as control treatments. The CCs and WBCs were collected prior to treatment (day 0), on day 1, and every third or seventh day thereafter until samples yielded negative results for Mx protein. Samples were examined for Mx protein expression via immunohistochemistry and immunoblotting procedures involving murine anti-Mx protein monoclonal antibody M143. RESULTS: After topical application of 10,000 U of rFeIFN-omega/eye, CCs stained for Mx protein for a minimum of 7 days, whereas WBCs were positive for Mx protein for a minimum of 31 days. After topical application of lower concentrations, CCs did not express Mx protein, in contrast to WBCs, which stained for Mx protein at 1,000 units for at least 1 day. Following oral administration, Mx protein was expressed in WBCs at rFeIFN-omega concentrations as low as 200 units, whereas CCs did not stain for Mx protein at any concentration. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that Mx protein expression (a marker of the biological response to rFeIFN-omega) in CCs and WBCs of rFeIFN-omega-treated cats depends on the dose of rFeIFN-omega, site of administration, and cell type.     

Effectiveness of using a mat filled with a peroxygen disinfectant to minimize shoe sole contamination in a veterinary hospital

OBJECTIVE: To determine the effectiveness of using a disinfectant mat filled with a peroxygen compound to prevent mechanical transmission of bacteria via contaminated footwear between the food animal ward and common breezeway of a veterinary teaching hospital. DESIGN: Observational study. SAMPLE POPULATION: Shoe soles of individuals entering and exiting from the ward. PROCEDURES: A mat filled with peroxygen disinfectant was placed at the entrance to the food animal ward, and participants wiped each shoe twice on the mat surface (n = 16) or walked on the mat surface but did not wipe their shoes (17) before entering and exiting from the ward. Swab specimens were collected from the shoe soles of participants before and after mat use and submitted for bacterial culture. RESULTS: For both study days, as participants entered the ward, median number of aerobic bacteria isolated from shoe swab specimens collected prior to use of the disinfectant mat was not significantly different from median number isolated after use of the disinfectant mat. However, as participants exited the ward, median number of aerobic bacteria isolated from shoe swab specimens collected prior to use of the disinfectant mat was significantly higher than median number isolated after use of the disinfectant mat. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that placing a mat filled with a peroxygen disinfectant at the exit from the food animal ward of a veterinary teaching hospital may help reduce mechanical transmission of bacteria on the footwear of individuals leaving the ward.     

In-mouth amylase activity can reduce perception of saltiness in starch-thickened foods

Sensory scores for saltiness and thickness obtained for savory liquids thickened with starches or the nonstarch hydrocolloid hydroxypropylmethyl cellulose (HPMC) were correlated with the panelists' amylase activity. Although higher enzyme activities were linked to lower thickness scores for systems thickened by starch, they were also associated with a decreased taste perception, particularly for starches retaining a granular structure after gelatinization (wheat and modified waxy maize). Microscopic evidence showed that the enzyme can disrupt such structures, and this is associated with a decreased mixing efficiency with water and consequently a reduced transport of tastant (sodium) to the saliva (aqueous) phase and to the taste buds. This explains the lower saltiness scores for subjects with higher amylase activity, even if they are associated with a lower perceived thickness.     

Molecular phylogeny and evolution of morphology in the social amoebas

The social amoebas (Dictyostelia) display conditional multicellularity in a wide variety of forms. Despite widespread interest in Dictyostelium discoideum as a model system, almost no molecular data exist from the rest of the group. We constructed the first molecular phylogeny of the Dictyostelia with parallel small subunit ribosomal RNA and a-tubulin data sets, and we found that dictyostelid taxonomy requires complete revision. A mapping of characters onto the phylogeny shows that the dominant trend in dictyostelid evolution is increased size and cell type specialization of fruiting structures, with some complex morphologies evolving several times independently. Thus, the latter may be controlled by only a few genes, making their underlying mechanisms relatively easy to unravel.     

Humanization of yeast to produce complex terminally sialylated glycoproteins

Yeast is a widely used recombinant protein expression system. We expanded its utility by engineering the yeast Pichia pastoris to secrete human glycoproteins with fully complex terminally sialylated N-glycans. After the knockout of four genes to eliminate yeast-specific glycosylation, we introduced 14 heterologous genes, allowing us to replicate the sequential steps of human glycosylation. The reported cell lines produce complex glycoproteins with greater than 90% terminal sialylation. Finally, to demonstrate the utility of these yeast strains, functional recombinant erythropoietin was produced.     

Evaluating the spatial range of the effect of synchronized antiparasitic treatments on the abundance of sea lice Caligus rogercresseyi (Boxshall & Bravo, 2000) in Chile

Sea lice are the most important ectoparasites affecting farmed salmonids in marine water worldwide and pharmacological treatments are widely used to control their abundance. Synchronization of antiparasitic treatments among closely located salmon farms has been recently evaluated as a promising strategy for improving treatment performance. However, the optimum distance at which farms should synchronize their treatments is not clear. We used a repeated measures linear mixed effects model to evaluate the impact of two nationwide treatment synchronization procedures conducted in Chile in 2014 and 2015 on subsequent adult lice counts up to 13 weeks after the procedure. Each treatment synchronization procedure consisted of two 2‐week synchronization windows, in which farms were required to treat their fish. A period of 3 weeks elapsed between the two windows. Treatment synchronization was measured as the number of neighbouring farms that treated their fish within a certain geographical threshold, each of them weighted by its distance from the farm of interest. We tested four different thresholds: 5, 10, 20 and 30 km. The results indicate that the abundance of adult lice on farms that synchronized treatments with their neighbours within a distance of 5 km was lower than the abundance on non‐synchronized farms from weeks 4 to 11 after the procedure. Our findings suggest the treatment synchronization effect was distance dependent and greater when neighbouring farms up to 5 km joined the procedure.     

Influence of pheromone emission on the attraction of California red scale males in citrus orchards

Attraction of California red scale males, Aonidiella aurantii (Maskell), to different release rates of the sex pheromone compound 3-methyl-6-isopropenyl-9-decen-1-yl acetate was evaluated in field trials. This study was aimed to study pheromone emission-response correlations and the existence of an optimum release rate that maximizes trapping efficacy. Release profiles of the pheromone dispensers deployed were determined by gas chromatography to estimate the various emission rates tested. The results reveal that the mean number of A. aurantii males caught correlates with the daily pheromone release rates by means of a quadratic model. The obtained model indicates the existence of a relative maximum of the captures corresponding to an optimum release rate of ca. 300 μg/day. Higher emission rates (up to 1 g/day) resulted in lower captures. Implications for the mating disruption technique are discussed.